Age Owner Branch data TLA Line data Source code
1 : : /*-------------------------------------------------------------------------
2 : : *
3 : : * verify_nbtree.c
4 : : * Verifies the integrity of nbtree indexes based on invariants.
5 : : *
6 : : * For B-Tree indexes, verification includes checking that each page in the
7 : : * target index has items in logical order as reported by an insertion scankey
8 : : * (the insertion scankey sort-wise NULL semantics are needed for
9 : : * verification).
10 : : *
11 : : * When index-to-heap verification is requested, a Bloom filter is used to
12 : : * fingerprint all tuples in the target index, as the index is traversed to
13 : : * verify its structure. A heap scan later uses Bloom filter probes to verify
14 : : * that every visible heap tuple has a matching index tuple.
15 : : *
16 : : *
17 : : * Copyright (c) 2017-2025, PostgreSQL Global Development Group
18 : : *
19 : : * IDENTIFICATION
20 : : * contrib/amcheck/verify_nbtree.c
21 : : *
22 : : *-------------------------------------------------------------------------
23 : : */
24 : : #include "postgres.h"
25 : :
26 : : #include "access/heaptoast.h"
27 : : #include "access/htup_details.h"
28 : : #include "access/nbtree.h"
29 : : #include "access/table.h"
30 : : #include "access/tableam.h"
31 : : #include "access/transam.h"
32 : : #include "access/xact.h"
33 : : #include "verify_common.h"
34 : : #include "catalog/index.h"
35 : : #include "catalog/pg_am.h"
36 : : #include "catalog/pg_opfamily_d.h"
37 : : #include "common/pg_prng.h"
38 : : #include "lib/bloomfilter.h"
39 : : #include "miscadmin.h"
40 : : #include "storage/smgr.h"
41 : : #include "utils/guc.h"
42 : : #include "utils/memutils.h"
43 : : #include "utils/snapmgr.h"
44 : :
45 : :
164 tgl@sss.pgh.pa.us 46 :CBC 328 : PG_MODULE_MAGIC_EXT(
47 : : .name = "amcheck",
48 : : .version = PG_VERSION
49 : : );
50 : :
51 : : /*
52 : : * A B-Tree cannot possibly have this many levels, since there must be one
53 : : * block per level, which is bound by the range of BlockNumber:
54 : : */
55 : : #define InvalidBtreeLevel ((uint32) InvalidBlockNumber)
56 : : #define BTreeTupleGetNKeyAtts(itup, rel) \
57 : : Min(IndexRelationGetNumberOfKeyAttributes(rel), BTreeTupleGetNAtts(itup, rel))
58 : :
59 : : /*
60 : : * State associated with verifying a B-Tree index
61 : : *
62 : : * target is the point of reference for a verification operation.
63 : : *
64 : : * Other B-Tree pages may be allocated, but those are always auxiliary (e.g.,
65 : : * they are current target's child pages). Conceptually, problems are only
66 : : * ever found in the current target page (or for a particular heap tuple during
67 : : * heapallindexed verification). Each page found by verification's left/right,
68 : : * top/bottom scan becomes the target exactly once.
69 : : */
70 : : typedef struct BtreeCheckState
71 : : {
72 : : /*
73 : : * Unchanging state, established at start of verification:
74 : : */
75 : :
76 : : /* B-Tree Index Relation and associated heap relation */
77 : : Relation rel;
78 : : Relation heaprel;
79 : : /* rel is heapkeyspace index? */
80 : : bool heapkeyspace;
81 : : /* ShareLock held on heap/index, rather than AccessShareLock? */
82 : : bool readonly;
83 : : /* Also verifying heap has no unindexed tuples? */
84 : : bool heapallindexed;
85 : : /* Also making sure non-pivot tuples can be found by new search? */
86 : : bool rootdescend;
87 : : /* Also check uniqueness constraint if index is unique */
88 : : bool checkunique;
89 : : /* Per-page context */
90 : : MemoryContext targetcontext;
91 : : /* Buffer access strategy */
92 : : BufferAccessStrategy checkstrategy;
93 : :
94 : : /*
95 : : * Info for uniqueness checking. Fill these fields once per index check.
96 : : */
97 : : IndexInfo *indexinfo;
98 : : Snapshot snapshot;
99 : :
100 : : /*
101 : : * Mutable state, for verification of particular page:
102 : : */
103 : :
104 : : /* Current target page */
105 : : Page target;
106 : : /* Target block number */
107 : : BlockNumber targetblock;
108 : : /* Target page's LSN */
109 : : XLogRecPtr targetlsn;
110 : :
111 : : /*
112 : : * Low key: high key of left sibling of target page. Used only for child
113 : : * verification. So, 'lowkey' is kept only when 'readonly' is set.
114 : : */
115 : : IndexTuple lowkey;
116 : :
117 : : /*
118 : : * The rightlink and incomplete split flag of block one level down to the
119 : : * target page, which was visited last time via downlink from target page.
120 : : * We use it to check for missing downlinks.
121 : : */
122 : : BlockNumber prevrightlink;
123 : : bool previncompletesplit;
124 : :
125 : : /*
126 : : * Mutable state, for optional heapallindexed verification:
127 : : */
128 : :
129 : : /* Bloom filter fingerprints B-Tree index */
130 : : bloom_filter *filter;
131 : : /* Debug counter */
132 : : int64 heaptuplespresent;
133 : : } BtreeCheckState;
134 : :
135 : : /*
136 : : * Starting point for verifying an entire B-Tree index level
137 : : */
138 : : typedef struct BtreeLevel
139 : : {
140 : : /* Level number (0 is leaf page level). */
141 : : uint32 level;
142 : :
143 : : /* Left most block on level. Scan of level begins here. */
144 : : BlockNumber leftmost;
145 : :
146 : : /* Is this level reported as "true" root level by meta page? */
147 : : bool istruerootlevel;
148 : : } BtreeLevel;
149 : :
150 : : /*
151 : : * Information about the last visible entry with current B-tree key. Used
152 : : * for validation of the unique constraint.
153 : : */
154 : : typedef struct BtreeLastVisibleEntry
155 : : {
156 : : BlockNumber blkno; /* Index block */
157 : : OffsetNumber offset; /* Offset on index block */
158 : : int postingIndex; /* Number in the posting list (-1 for
159 : : * non-deduplicated tuples) */
160 : : ItemPointer tid; /* Heap tid */
161 : : } BtreeLastVisibleEntry;
162 : :
163 : : /*
164 : : * arguments for the bt_index_check_callback callback
165 : : */
166 : : typedef struct BTCallbackState
167 : : {
168 : : bool parentcheck;
169 : : bool heapallindexed;
170 : : bool rootdescend;
171 : : bool checkunique;
172 : : } BTCallbackState;
173 : :
3103 andres@anarazel.de 174 : 93 : PG_FUNCTION_INFO_V1(bt_index_check);
175 : 64 : PG_FUNCTION_INFO_V1(bt_index_parent_check);
176 : :
177 : : static void bt_index_check_callback(Relation indrel, Relation heaprel,
178 : : void *state, bool readonly);
179 : : static void bt_check_every_level(Relation rel, Relation heaprel,
180 : : bool heapkeyspace, bool readonly, bool heapallindexed,
181 : : bool rootdescend, bool checkunique);
182 : : static BtreeLevel bt_check_level_from_leftmost(BtreeCheckState *state,
183 : : BtreeLevel level);
184 : : static bool bt_leftmost_ignoring_half_dead(BtreeCheckState *state,
185 : : BlockNumber start,
186 : : BTPageOpaque start_opaque);
187 : : static void bt_recheck_sibling_links(BtreeCheckState *state,
188 : : BlockNumber btpo_prev_from_target,
189 : : BlockNumber leftcurrent);
190 : : static bool heap_entry_is_visible(BtreeCheckState *state, ItemPointer tid);
191 : : static void bt_report_duplicate(BtreeCheckState *state,
192 : : BtreeLastVisibleEntry *lVis,
193 : : ItemPointer nexttid,
194 : : BlockNumber nblock, OffsetNumber noffset,
195 : : int nposting);
196 : : static void bt_entry_unique_check(BtreeCheckState *state, IndexTuple itup,
197 : : BlockNumber targetblock, OffsetNumber offset,
198 : : BtreeLastVisibleEntry *lVis);
199 : : static void bt_target_page_check(BtreeCheckState *state);
200 : : static BTScanInsert bt_right_page_check_scankey(BtreeCheckState *state,
201 : : OffsetNumber *rightfirstoffset);
202 : : static void bt_child_check(BtreeCheckState *state, BTScanInsert targetkey,
203 : : OffsetNumber downlinkoffnum);
204 : : static void bt_child_highkey_check(BtreeCheckState *state,
205 : : OffsetNumber target_downlinkoffnum,
206 : : Page loaded_child,
207 : : uint32 target_level);
208 : : static void bt_downlink_missing_check(BtreeCheckState *state, bool rightsplit,
209 : : BlockNumber blkno, Page page);
210 : : static void bt_tuple_present_callback(Relation index, ItemPointer tid,
211 : : Datum *values, bool *isnull,
212 : : bool tupleIsAlive, void *checkstate);
213 : : static IndexTuple bt_normalize_tuple(BtreeCheckState *state,
214 : : IndexTuple itup);
215 : : static inline IndexTuple bt_posting_plain_tuple(IndexTuple itup, int n);
216 : : static bool bt_rootdescend(BtreeCheckState *state, IndexTuple itup);
217 : : static inline bool offset_is_negative_infinity(BTPageOpaque opaque,
218 : : OffsetNumber offset);
219 : : static inline bool invariant_l_offset(BtreeCheckState *state, BTScanInsert key,
220 : : OffsetNumber upperbound);
221 : : static inline bool invariant_leq_offset(BtreeCheckState *state,
222 : : BTScanInsert key,
223 : : OffsetNumber upperbound);
224 : : static inline bool invariant_g_offset(BtreeCheckState *state, BTScanInsert key,
225 : : OffsetNumber lowerbound);
226 : : static inline bool invariant_l_nontarget_offset(BtreeCheckState *state,
227 : : BTScanInsert key,
228 : : BlockNumber nontargetblock,
229 : : Page nontarget,
230 : : OffsetNumber upperbound);
231 : : static Page palloc_btree_page(BtreeCheckState *state, BlockNumber blocknum);
232 : : static inline BTScanInsert bt_mkscankey_pivotsearch(Relation rel,
233 : : IndexTuple itup);
234 : : static ItemId PageGetItemIdCareful(BtreeCheckState *state, BlockNumber block,
235 : : Page page, OffsetNumber offset);
236 : : static inline ItemPointer BTreeTupleGetHeapTIDCareful(BtreeCheckState *state,
237 : : IndexTuple itup, bool nonpivot);
238 : : static inline ItemPointer BTreeTupleGetPointsToTID(IndexTuple itup);
239 : :
240 : : /*
241 : : * bt_index_check(index regclass, heapallindexed boolean, checkunique boolean)
242 : : *
243 : : * Verify integrity of B-Tree index.
244 : : *
245 : : * Acquires AccessShareLock on heap & index relations. Does not consider
246 : : * invariants that exist between parent/child pages. Optionally verifies
247 : : * that heap does not contain any unindexed or incorrectly indexed tuples.
248 : : */
249 : : Datum
250 : 3926 : bt_index_check(PG_FUNCTION_ARGS)
251 : : {
252 : 3926 : Oid indrelid = PG_GETARG_OID(0);
253 : : BTCallbackState args;
254 : :
161 tomas.vondra@postgre 255 : 3926 : args.heapallindexed = false;
256 : 3926 : args.rootdescend = false;
257 : 3926 : args.parentcheck = false;
258 : 3926 : args.checkunique = false;
259 : :
679 akorotkov@postgresql 260 [ + + ]: 3926 : if (PG_NARGS() >= 2)
161 tomas.vondra@postgre 261 : 3920 : args.heapallindexed = PG_GETARG_BOOL(1);
262 [ + + ]: 3926 : if (PG_NARGS() >= 3)
263 : 682 : args.checkunique = PG_GETARG_BOOL(2);
264 : :
265 : 3926 : amcheck_lock_relation_and_check(indrelid, BTREE_AM_OID,
266 : : bt_index_check_callback,
267 : : AccessShareLock, &args);
268 : :
3103 andres@anarazel.de 269 : 3900 : PG_RETURN_VOID();
270 : : }
271 : :
272 : : /*
273 : : * bt_index_parent_check(index regclass, heapallindexed boolean, rootdescend boolean, checkunique boolean)
274 : : *
275 : : * Verify integrity of B-Tree index.
276 : : *
277 : : * Acquires ShareLock on heap & index relations. Verifies that downlinks in
278 : : * parent pages are valid lower bounds on child pages. Optionally verifies
279 : : * that heap does not contain any unindexed or incorrectly indexed tuples.
280 : : */
281 : : Datum
282 : 61 : bt_index_parent_check(PG_FUNCTION_ARGS)
283 : : {
284 : 61 : Oid indrelid = PG_GETARG_OID(0);
285 : : BTCallbackState args;
286 : :
161 tomas.vondra@postgre 287 : 61 : args.heapallindexed = false;
288 : 61 : args.rootdescend = false;
289 : 61 : args.parentcheck = true;
290 : 61 : args.checkunique = false;
291 : :
2362 pg@bowt.ie 292 [ + + ]: 61 : if (PG_NARGS() >= 2)
161 tomas.vondra@postgre 293 : 55 : args.heapallindexed = PG_GETARG_BOOL(1);
679 akorotkov@postgresql 294 [ + + ]: 61 : if (PG_NARGS() >= 3)
161 tomas.vondra@postgre 295 : 52 : args.rootdescend = PG_GETARG_BOOL(2);
296 [ + + ]: 61 : if (PG_NARGS() >= 4)
297 : 26 : args.checkunique = PG_GETARG_BOOL(3);
298 : :
299 : 61 : amcheck_lock_relation_and_check(indrelid, BTREE_AM_OID,
300 : : bt_index_check_callback,
301 : : ShareLock, &args);
302 : :
3103 andres@anarazel.de 303 : 43 : PG_RETURN_VOID();
304 : : }
305 : :
306 : : /*
307 : : * Helper for bt_index_[parent_]check, coordinating the bulk of the work.
308 : : */
309 : : static void
161 tomas.vondra@postgre 310 : 3981 : bt_index_check_callback(Relation indrel, Relation heaprel, void *state, bool readonly)
311 : : {
312 : 3981 : BTCallbackState *args = (BTCallbackState *) state;
313 : : bool heapkeyspace,
314 : : allequalimage;
315 : :
316 [ + + ]: 3981 : if (!smgrexists(RelationGetSmgr(indrel), MAIN_FORKNUM))
3103 andres@anarazel.de 317 [ + - ]: 18 : ereport(ERROR,
318 : : (errcode(ERRCODE_INDEX_CORRUPTED),
319 : : errmsg("index \"%s\" lacks a main relation fork",
320 : : RelationGetRelationName(indrel))));
321 : :
322 : : /* Extract metadata from metapage, and sanitize it in passing */
161 tomas.vondra@postgre 323 : 3963 : _bt_metaversion(indrel, &heapkeyspace, &allequalimage);
324 [ + + - + ]: 3963 : if (allequalimage && !heapkeyspace)
161 tomas.vondra@postgre 325 [ # # ]:UBC 0 : ereport(ERROR,
326 : : (errcode(ERRCODE_INDEX_CORRUPTED),
327 : : errmsg("index \"%s\" metapage has equalimage field set on unsupported nbtree version",
328 : : RelationGetRelationName(indrel))));
161 tomas.vondra@postgre 329 [ + + - + ]:CBC 3963 : if (allequalimage && !_bt_allequalimage(indrel, false))
330 : : {
161 tomas.vondra@postgre 331 :UBC 0 : bool has_interval_ops = false;
332 : :
333 [ # # ]: 0 : for (int i = 0; i < IndexRelationGetNumberOfKeyAttributes(indrel); i++)
334 [ # # ]: 0 : if (indrel->rd_opfamily[i] == INTERVAL_BTREE_FAM_OID)
335 : : {
336 : 0 : has_interval_ops = true;
337 [ # # # # ]: 0 : ereport(ERROR,
338 : : (errcode(ERRCODE_INDEX_CORRUPTED),
339 : : errmsg("index \"%s\" metapage incorrectly indicates that deduplication is safe",
340 : : RelationGetRelationName(indrel)),
341 : : has_interval_ops
342 : : ? errhint("This is known of \"interval\" indexes last built on a version predating 2023-11.")
343 : : : 0));
344 : : }
345 : : }
346 : :
347 : : /* Check index, possibly against table it is an index on */
161 tomas.vondra@postgre 348 :CBC 3963 : bt_check_every_level(indrel, heaprel, heapkeyspace, readonly,
349 : 3963 : args->heapallindexed, args->rootdescend, args->checkunique);
2217 pg@bowt.ie 350 : 3943 : }
351 : :
352 : : /*
353 : : * Main entry point for B-Tree SQL-callable functions. Walks the B-Tree in
354 : : * logical order, verifying invariants as it goes. Optionally, verification
355 : : * checks if the heap relation contains any tuples that are not represented in
356 : : * the index but should be.
357 : : *
358 : : * It is the caller's responsibility to acquire appropriate heavyweight lock on
359 : : * the index relation, and advise us if extra checks are safe when a ShareLock
360 : : * is held. (A lock of the same type must also have been acquired on the heap
361 : : * relation.)
362 : : *
363 : : * A ShareLock is generally assumed to prevent any kind of physical
364 : : * modification to the index structure, including modifications that VACUUM may
365 : : * make. This does not include setting of the LP_DEAD bit by concurrent index
366 : : * scans, although that is just metadata that is not able to directly affect
367 : : * any check performed here. Any concurrent process that might act on the
368 : : * LP_DEAD bit being set (recycle space) requires a heavyweight lock that
369 : : * cannot be held while we hold a ShareLock. (Besides, even if that could
370 : : * happen, the ad-hoc recycling when a page might otherwise split is performed
371 : : * per-page, and requires an exclusive buffer lock, which wouldn't cause us
372 : : * trouble. _bt_delitems_vacuum() may only delete leaf items, and so the extra
373 : : * parent/child check cannot be affected.)
374 : : */
375 : : static void
2362 376 : 3963 : bt_check_every_level(Relation rel, Relation heaprel, bool heapkeyspace,
377 : : bool readonly, bool heapallindexed, bool rootdescend,
378 : : bool checkunique)
379 : : {
380 : : BtreeCheckState *state;
381 : : Page metapage;
382 : : BTMetaPageData *metad;
383 : : uint32 previouslevel;
384 : : BtreeLevel current;
2716 andres@anarazel.de 385 : 3963 : Snapshot snapshot = SnapshotAny;
386 : :
1975 pg@bowt.ie 387 [ + + ]: 3963 : if (!readonly)
388 [ + + ]: 3914 : elog(DEBUG1, "verifying consistency of tree structure for index \"%s\"",
389 : : RelationGetRelationName(rel));
390 : : else
391 [ + + ]: 49 : elog(DEBUG1, "verifying consistency of tree structure for index \"%s\" with cross-level checks",
392 : : RelationGetRelationName(rel));
393 : :
394 : : /*
395 : : * This assertion matches the one in index_getnext_tid(). See page
396 : : * recycling/"visible to everyone" notes in nbtree README.
397 : : */
1851 andres@anarazel.de 398 [ - + ]: 3963 : Assert(TransactionIdIsValid(RecentXmin));
399 : :
400 : : /*
401 : : * Initialize state for entire verification operation
402 : : */
2691 teodor@sigaev.ru 403 : 3963 : state = palloc0(sizeof(BtreeCheckState));
3103 andres@anarazel.de 404 : 3963 : state->rel = rel;
2716 405 : 3963 : state->heaprel = heaprel;
2362 pg@bowt.ie 406 : 3963 : state->heapkeyspace = heapkeyspace;
3103 andres@anarazel.de 407 : 3963 : state->readonly = readonly;
2716 408 : 3963 : state->heapallindexed = heapallindexed;
2362 pg@bowt.ie 409 : 3963 : state->rootdescend = rootdescend;
679 akorotkov@postgresql 410 : 3963 : state->checkunique = checkunique;
411 : 3963 : state->snapshot = InvalidSnapshot;
412 : :
2716 andres@anarazel.de 413 [ + + ]: 3963 : if (state->heapallindexed)
414 : : {
415 : : int64 total_pages;
416 : : int64 total_elems;
417 : : uint64 seed;
418 : :
419 : : /*
420 : : * Size Bloom filter based on estimated number of tuples in index,
421 : : * while conservatively assuming that each block must contain at least
422 : : * MaxTIDsPerBTreePage / 3 "plain" tuples -- see
423 : : * bt_posting_plain_tuple() for definition, and details of how posting
424 : : * list tuples are handled.
425 : : */
2240 pg@bowt.ie 426 : 62 : total_pages = RelationGetNumberOfBlocks(rel);
2019 427 : 62 : total_elems = Max(total_pages * (MaxTIDsPerBTreePage / 3),
428 : : (int64) state->rel->rd_rel->reltuples);
429 : : /* Generate a random seed to avoid repetition */
1378 tgl@sss.pgh.pa.us 430 : 62 : seed = pg_prng_uint64(&pg_global_prng_state);
431 : : /* Create Bloom filter to fingerprint index */
2716 andres@anarazel.de 432 : 62 : state->filter = bloom_create(total_elems, maintenance_work_mem, seed);
433 : 62 : state->heaptuplespresent = 0;
434 : :
435 : : /*
436 : : * Register our own snapshot in !readonly case, rather than asking
437 : : * table_index_build_scan() to do this for us later. This needs to
438 : : * happen before index fingerprinting begins, so we can later be
439 : : * certain that index fingerprinting should have reached all tuples
440 : : * returned by table_index_build_scan().
441 : : */
442 [ + + ]: 62 : if (!state->readonly)
443 : : {
444 : 35 : snapshot = RegisterSnapshot(GetTransactionSnapshot());
445 : :
446 : : /*
447 : : * GetTransactionSnapshot() always acquires a new MVCC snapshot in
448 : : * READ COMMITTED mode. A new snapshot is guaranteed to have all
449 : : * the entries it requires in the index.
450 : : *
451 : : * We must defend against the possibility that an old xact
452 : : * snapshot was returned at higher isolation levels when that
453 : : * snapshot is not safe for index scans of the target index. This
454 : : * is possible when the snapshot sees tuples that are before the
455 : : * index's indcheckxmin horizon. Throwing an error here should be
456 : : * very rare. It doesn't seem worth using a secondary snapshot to
457 : : * avoid this.
458 : : */
459 [ - + - - ]: 35 : if (IsolationUsesXactSnapshot() && rel->rd_index->indcheckxmin &&
2716 andres@anarazel.de 460 [ # # ]:UBC 0 : !TransactionIdPrecedes(HeapTupleHeaderGetXmin(rel->rd_indextuple->t_data),
461 : : snapshot->xmin))
462 [ # # ]: 0 : ereport(ERROR,
463 : : (errcode(ERRCODE_T_R_SERIALIZATION_FAILURE),
464 : : errmsg("index \"%s\" cannot be verified using transaction snapshot",
465 : : RelationGetRelationName(rel))));
466 : : }
467 : : }
468 : :
469 : : /*
470 : : * We need a snapshot to check the uniqueness of the index. For better
471 : : * performance take it once per index check. If snapshot already taken
472 : : * reuse it.
473 : : */
679 akorotkov@postgresql 474 [ + + ]:CBC 3963 : if (state->checkunique)
475 : : {
476 : 704 : state->indexinfo = BuildIndexInfo(state->rel);
477 [ + + ]: 704 : if (state->indexinfo->ii_Unique)
478 : : {
479 [ + + ]: 634 : if (snapshot != SnapshotAny)
480 : 7 : state->snapshot = snapshot;
481 : : else
482 : 627 : state->snapshot = RegisterSnapshot(GetTransactionSnapshot());
483 : : }
484 : : }
485 : :
2362 pg@bowt.ie 486 [ + + - + ]: 3963 : Assert(!state->rootdescend || state->readonly);
487 [ + + - + ]: 3963 : if (state->rootdescend && !state->heapkeyspace)
2362 pg@bowt.ie 488 [ # # ]:UBC 0 : ereport(ERROR,
489 : : (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
490 : : errmsg("cannot verify that tuples from index \"%s\" can each be found by an independent index search",
491 : : RelationGetRelationName(rel)),
492 : : errhint("Only B-Tree version 4 indexes support rootdescend verification.")));
493 : :
494 : : /* Create context for page */
3103 andres@anarazel.de 495 :CBC 3963 : state->targetcontext = AllocSetContextCreate(CurrentMemoryContext,
496 : : "amcheck context",
497 : : ALLOCSET_DEFAULT_SIZES);
498 : 3963 : state->checkstrategy = GetAccessStrategy(BAS_BULKREAD);
499 : :
500 : : /* Get true root block from meta-page */
501 : 3963 : metapage = palloc_btree_page(state, BTREE_METAPAGE);
502 : 3963 : metad = BTPageGetMeta(metapage);
503 : :
504 : : /*
505 : : * Certain deletion patterns can result in "skinny" B-Tree indexes, where
506 : : * the fast root and true root differ.
507 : : *
508 : : * Start from the true root, not the fast root, unlike conventional index
509 : : * scans. This approach is more thorough, and removes the risk of
510 : : * following a stale fast root from the meta page.
511 : : */
512 [ + + ]: 3963 : if (metad->btm_fastroot != metad->btm_root)
513 [ - + ]: 13 : ereport(DEBUG1,
514 : : (errcode(ERRCODE_NO_DATA),
515 : : errmsg_internal("harmless fast root mismatch in index \"%s\"",
516 : : RelationGetRelationName(rel)),
517 : : errdetail_internal("Fast root block %u (level %u) differs from true root block %u (level %u).",
518 : : metad->btm_fastroot, metad->btm_fastlevel,
519 : : metad->btm_root, metad->btm_level)));
520 : :
521 : : /*
522 : : * Starting at the root, verify every level. Move left to right, top to
523 : : * bottom. Note that there may be no pages other than the meta page (meta
524 : : * page can indicate that root is P_NONE when the index is totally empty).
525 : : */
526 : 3963 : previouslevel = InvalidBtreeLevel;
527 : 3963 : current.level = metad->btm_level;
528 : 3963 : current.leftmost = metad->btm_root;
529 : 3963 : current.istruerootlevel = true;
530 [ + + ]: 6443 : while (current.leftmost != P_NONE)
531 : : {
532 : : /*
533 : : * Verify this level, and get left most page for next level down, if
534 : : * not at leaf level
535 : : */
536 : 2498 : current = bt_check_level_from_leftmost(state, current);
537 : :
538 [ - + ]: 2480 : if (current.leftmost == InvalidBlockNumber)
3103 andres@anarazel.de 539 [ # # ]:UBC 0 : ereport(ERROR,
540 : : (errcode(ERRCODE_INDEX_CORRUPTED),
541 : : errmsg("index \"%s\" has no valid pages on level below %u or first level",
542 : : RelationGetRelationName(rel), previouslevel)));
543 : :
3103 andres@anarazel.de 544 :CBC 2480 : previouslevel = current.level;
545 : : }
546 : :
547 : : /*
548 : : * * Check whether heap contains unindexed/malformed tuples *
549 : : */
2716 550 [ + + ]: 3945 : if (state->heapallindexed)
551 : : {
552 : 55 : IndexInfo *indexinfo = BuildIndexInfo(state->rel);
553 : : TableScanDesc scan;
554 : :
555 : : /*
556 : : * Create our own scan for table_index_build_scan(), rather than
557 : : * getting it to do so for us. This is required so that we can
558 : : * actually use the MVCC snapshot registered earlier in !readonly
559 : : * case.
560 : : *
561 : : * Note that table_index_build_scan() calls heap_endscan() for us.
562 : : */
2355 563 : 55 : scan = table_beginscan_strat(state->heaprel, /* relation */
564 : : snapshot, /* snapshot */
565 : : 0, /* number of keys */
566 : : NULL, /* scan key */
567 : : true, /* buffer access strategy OK */
568 : : true); /* syncscan OK? */
569 : :
570 : : /*
571 : : * Scan will behave as the first scan of a CREATE INDEX CONCURRENTLY
572 : : * behaves in !readonly case.
573 : : *
574 : : * It's okay that we don't actually use the same lock strength for the
575 : : * heap relation as any other ii_Concurrent caller would in !readonly
576 : : * case. We have no reason to care about a concurrent VACUUM
577 : : * operation, since there isn't going to be a second scan of the heap
578 : : * that needs to be sure that there was no concurrent recycling of
579 : : * TIDs.
580 : : */
2716 581 : 53 : indexinfo->ii_Concurrent = !state->readonly;
582 : :
583 : : /*
584 : : * Don't wait for uncommitted tuple xact commit/abort when index is a
585 : : * unique index on a catalog (or an index used by an exclusion
586 : : * constraint). This could otherwise happen in the readonly case.
587 : : */
588 : 53 : indexinfo->ii_Unique = false;
589 : 53 : indexinfo->ii_ExclusionOps = NULL;
590 : 53 : indexinfo->ii_ExclusionProcs = NULL;
591 : 53 : indexinfo->ii_ExclusionStrats = NULL;
592 : :
593 [ + + ]: 53 : elog(DEBUG1, "verifying that tuples from index \"%s\" are present in \"%s\"",
594 : : RelationGetRelationName(state->rel),
595 : : RelationGetRelationName(state->heaprel));
596 : :
2349 alvherre@alvh.no-ip. 597 : 53 : table_index_build_scan(state->heaprel, state->rel, indexinfo, true, false,
598 : : bt_tuple_present_callback, state, scan);
599 : :
2716 andres@anarazel.de 600 [ + + ]: 53 : ereport(DEBUG1,
601 : : (errmsg_internal("finished verifying presence of " INT64_FORMAT " tuples from table \"%s\" with bitset %.2f%% set",
602 : : state->heaptuplespresent, RelationGetRelationName(heaprel),
603 : : 100.0 * bloom_prop_bits_set(state->filter))));
604 : :
605 [ + + ]: 53 : if (snapshot != SnapshotAny)
606 : 30 : UnregisterSnapshot(snapshot);
607 : :
608 : 53 : bloom_free(state->filter);
609 : : }
610 : :
611 : : /* Be tidy: */
679 akorotkov@postgresql 612 [ + + + + ]: 3943 : if (snapshot == SnapshotAny && state->snapshot != InvalidSnapshot)
613 : 627 : UnregisterSnapshot(state->snapshot);
3103 andres@anarazel.de 614 : 3943 : MemoryContextDelete(state->targetcontext);
615 : 3943 : }
616 : :
617 : : /*
618 : : * Given a left-most block at some level, move right, verifying each page
619 : : * individually (with more verification across pages for "readonly"
620 : : * callers). Caller should pass the true root page as the leftmost initially,
621 : : * working their way down by passing what is returned for the last call here
622 : : * until level 0 (leaf page level) was reached.
623 : : *
624 : : * Returns state for next call, if any. This includes left-most block number
625 : : * one level lower that should be passed on next level/call, which is set to
626 : : * P_NONE on last call here (when leaf level is verified). Level numbers
627 : : * follow the nbtree convention: higher levels have higher numbers, because new
628 : : * levels are added only due to a root page split. Note that prior to the
629 : : * first root page split, the root is also a leaf page, so there is always a
630 : : * level 0 (leaf level), and it's always the last level processed.
631 : : *
632 : : * Note on memory management: State's per-page context is reset here, between
633 : : * each call to bt_target_page_check().
634 : : */
635 : : static BtreeLevel
636 : 2498 : bt_check_level_from_leftmost(BtreeCheckState *state, BtreeLevel level)
637 : : {
638 : : /* State to establish early, concerning entire level */
639 : : BTPageOpaque opaque;
640 : : MemoryContext oldcontext;
641 : : BtreeLevel nextleveldown;
642 : :
643 : : /* Variables for iterating across level using right links */
644 : 2498 : BlockNumber leftcurrent = P_NONE;
645 : 2498 : BlockNumber current = level.leftmost;
646 : :
647 : : /* Initialize return state */
648 : 2498 : nextleveldown.leftmost = InvalidBlockNumber;
649 : 2498 : nextleveldown.level = InvalidBtreeLevel;
650 : 2498 : nextleveldown.istruerootlevel = false;
651 : :
652 : : /* Use page-level context for duration of this call */
653 : 2498 : oldcontext = MemoryContextSwitchTo(state->targetcontext);
654 : :
1975 pg@bowt.ie 655 [ + + + + : 2498 : elog(DEBUG1, "verifying level %u%s", level.level,
+ - ]
656 : : level.istruerootlevel ?
657 : : " (true root level)" : level.level == 0 ? " (leaf level)" : "");
658 : :
2005 akorotkov@postgresql 659 : 2498 : state->prevrightlink = InvalidBlockNumber;
660 : 2498 : state->previncompletesplit = false;
661 : :
662 : : do
663 : : {
664 : : /* Don't rely on CHECK_FOR_INTERRUPTS() calls at lower level */
3103 andres@anarazel.de 665 [ - + ]: 9301 : CHECK_FOR_INTERRUPTS();
666 : :
667 : : /* Initialize state for this iteration */
668 : 9301 : state->targetblock = current;
669 : 9301 : state->target = palloc_btree_page(state, state->targetblock);
670 : 9289 : state->targetlsn = PageGetLSN(state->target);
671 : :
1254 michael@paquier.xyz 672 : 9289 : opaque = BTPageGetOpaque(state->target);
673 : :
3103 andres@anarazel.de 674 [ - + ]: 9289 : if (P_IGNORE(opaque))
675 : : {
676 : : /*
677 : : * Since there cannot be a concurrent VACUUM operation in readonly
678 : : * mode, and since a page has no links within other pages
679 : : * (siblings and parent) once it is marked fully deleted, it
680 : : * should be impossible to land on a fully deleted page in
681 : : * readonly mode. See bt_child_check() for further details.
682 : : *
683 : : * The bt_child_check() P_ISDELETED() check is repeated here so
684 : : * that pages that are only reachable through sibling links get
685 : : * checked.
686 : : */
2691 teodor@sigaev.ru 687 [ # # # # ]:UBC 0 : if (state->readonly && P_ISDELETED(opaque))
688 [ # # ]: 0 : ereport(ERROR,
689 : : (errcode(ERRCODE_INDEX_CORRUPTED),
690 : : errmsg("downlink or sibling link points to deleted block in index \"%s\"",
691 : : RelationGetRelationName(state->rel)),
692 : : errdetail_internal("Block=%u left block=%u left link from block=%u.",
693 : : current, leftcurrent, opaque->btpo_prev)));
694 : :
3103 andres@anarazel.de 695 [ # # ]: 0 : if (P_RIGHTMOST(opaque))
696 [ # # ]: 0 : ereport(ERROR,
697 : : (errcode(ERRCODE_INDEX_CORRUPTED),
698 : : errmsg("block %u fell off the end of index \"%s\"",
699 : : current, RelationGetRelationName(state->rel))));
700 : : else
701 [ # # ]: 0 : ereport(DEBUG1,
702 : : (errcode(ERRCODE_NO_DATA),
703 : : errmsg_internal("block %u of index \"%s\" concurrently deleted",
704 : : current, RelationGetRelationName(state->rel))));
705 : 0 : goto nextpage;
706 : : }
3103 andres@anarazel.de 707 [ + + ]:CBC 9289 : else if (nextleveldown.leftmost == InvalidBlockNumber)
708 : : {
709 : : /*
710 : : * A concurrent page split could make the caller supplied leftmost
711 : : * block no longer contain the leftmost page, or no longer be the
712 : : * true root, but where that isn't possible due to heavyweight
713 : : * locking, check that the first valid page meets caller's
714 : : * expectations.
715 : : */
716 [ + + ]: 2486 : if (state->readonly)
717 : : {
677 noah@leadboat.com 718 [ - + ]: 44 : if (!bt_leftmost_ignoring_half_dead(state, current, opaque))
3103 andres@anarazel.de 719 [ # # ]:UBC 0 : ereport(ERROR,
720 : : (errcode(ERRCODE_INDEX_CORRUPTED),
721 : : errmsg("block %u is not leftmost in index \"%s\"",
722 : : current, RelationGetRelationName(state->rel))));
723 : :
3103 andres@anarazel.de 724 [ + + - + ]:CBC 44 : if (level.istruerootlevel && !P_ISROOT(opaque))
3103 andres@anarazel.de 725 [ # # ]:UBC 0 : ereport(ERROR,
726 : : (errcode(ERRCODE_INDEX_CORRUPTED),
727 : : errmsg("block %u is not true root in index \"%s\"",
728 : : current, RelationGetRelationName(state->rel))));
729 : : }
730 : :
731 : : /*
732 : : * Before beginning any non-trivial examination of level, prepare
733 : : * state for next bt_check_level_from_leftmost() invocation for
734 : : * the next level for the next level down (if any).
735 : : *
736 : : * There should be at least one non-ignorable page per level,
737 : : * unless this is the leaf level, which is assumed by caller to be
738 : : * final level.
739 : : */
3103 andres@anarazel.de 740 [ + + ]:CBC 2486 : if (!P_ISLEAF(opaque))
741 : : {
742 : : IndexTuple itup;
743 : : ItemId itemid;
744 : :
745 : : /* Internal page -- downlink gets leftmost on next level */
2326 pg@bowt.ie 746 : 555 : itemid = PageGetItemIdCareful(state, state->targetblock,
747 : : state->target,
748 [ + + ]: 555 : P_FIRSTDATAKEY(opaque));
3103 andres@anarazel.de 749 : 555 : itup = (IndexTuple) PageGetItem(state->target, itemid);
2091 pg@bowt.ie 750 : 555 : nextleveldown.leftmost = BTreeTupleGetDownLink(itup);
1655 751 : 555 : nextleveldown.level = opaque->btpo_level - 1;
752 : : }
753 : : else
754 : : {
755 : : /*
756 : : * Leaf page -- final level caller must process.
757 : : *
758 : : * Note that this could also be the root page, if there has
759 : : * been no root page split yet.
760 : : */
3103 andres@anarazel.de 761 : 1931 : nextleveldown.leftmost = P_NONE;
762 : 1931 : nextleveldown.level = InvalidBtreeLevel;
763 : : }
764 : :
765 : : /*
766 : : * Finished setting up state for this call/level. Control will
767 : : * never end up back here in any future loop iteration for this
768 : : * level.
769 : : */
770 : : }
771 : :
772 : : /*
773 : : * Sibling links should be in mutual agreement. There arises
774 : : * leftcurrent == P_NONE && btpo_prev != P_NONE when the left sibling
775 : : * of the parent's low-key downlink is half-dead. (A half-dead page
776 : : * has no downlink from its parent.) Under heavyweight locking, the
777 : : * last bt_leftmost_ignoring_half_dead() validated this btpo_prev.
778 : : * Without heavyweight locking, validation of the P_NONE case remains
779 : : * unimplemented.
780 : : */
677 noah@leadboat.com 781 [ + + - + ]: 9289 : if (opaque->btpo_prev != leftcurrent && leftcurrent != P_NONE)
1855 pg@bowt.ie 782 :UBC 0 : bt_recheck_sibling_links(state, opaque->btpo_prev, leftcurrent);
783 : :
784 : : /* Check level */
1655 pg@bowt.ie 785 [ - + ]:CBC 9289 : if (level.level != opaque->btpo_level)
3103 andres@anarazel.de 786 [ # # ]:UBC 0 : ereport(ERROR,
787 : : (errcode(ERRCODE_INDEX_CORRUPTED),
788 : : errmsg("leftmost down link for level points to block in index \"%s\" whose level is not one level down",
789 : : RelationGetRelationName(state->rel)),
790 : : errdetail_internal("Block pointed to=%u expected level=%u level in pointed to block=%u.",
791 : : current, level.level, opaque->btpo_level)));
792 : :
793 : : /* Verify invariants for page */
3103 andres@anarazel.de 794 :CBC 9289 : bt_target_page_check(state);
795 : :
796 : 9283 : nextpage:
797 : :
798 : : /* Try to detect circular links */
799 [ + - - + ]: 9283 : if (current == leftcurrent || current == opaque->btpo_prev)
3103 andres@anarazel.de 800 [ # # ]:UBC 0 : ereport(ERROR,
801 : : (errcode(ERRCODE_INDEX_CORRUPTED),
802 : : errmsg("circular link chain found in block %u of index \"%s\"",
803 : : current, RelationGetRelationName(state->rel))));
804 : :
2005 akorotkov@postgresql 805 :CBC 9283 : leftcurrent = current;
806 : 9283 : current = opaque->btpo_next;
807 : :
808 [ + + ]: 9283 : if (state->lowkey)
809 : : {
810 [ - + ]: 1862 : Assert(state->readonly);
811 : 1862 : pfree(state->lowkey);
812 : 1862 : state->lowkey = NULL;
813 : : }
814 : :
815 : : /*
816 : : * Copy current target high key as the low key of right sibling.
817 : : * Allocate memory in upper level context, so it would be cleared
818 : : * after reset of target context.
819 : : *
820 : : * We only need the low key in corner cases of checking child high
821 : : * keys. We use high key only when incomplete split on the child level
822 : : * falls to the boundary of pages on the target level. See
823 : : * bt_child_highkey_check() for details. So, typically we won't end
824 : : * up doing anything with low key, but it's simpler for general case
825 : : * high key verification to always have it available.
826 : : *
827 : : * The correctness of managing low key in the case of concurrent
828 : : * splits wasn't investigated yet. Thankfully we only need low key
829 : : * for readonly verification and concurrent splits won't happen.
830 : : */
831 [ + + + + ]: 9283 : if (state->readonly && !P_RIGHTMOST(opaque))
832 : : {
833 : : IndexTuple itup;
834 : : ItemId itemid;
835 : :
836 : 1862 : itemid = PageGetItemIdCareful(state, state->targetblock,
837 : : state->target, P_HIKEY);
838 : 1862 : itup = (IndexTuple) PageGetItem(state->target, itemid);
839 : :
840 : 1862 : state->lowkey = MemoryContextAlloc(oldcontext, IndexTupleSize(itup));
841 : 1862 : memcpy(state->lowkey, itup, IndexTupleSize(itup));
842 : : }
843 : :
844 : : /* Free page and associated memory for this iteration */
3103 andres@anarazel.de 845 : 9283 : MemoryContextReset(state->targetcontext);
846 : : }
847 [ + + ]: 9283 : while (current != P_NONE);
848 : :
2005 akorotkov@postgresql 849 [ - + ]: 2480 : if (state->lowkey)
850 : : {
2005 akorotkov@postgresql 851 [ # # ]:UBC 0 : Assert(state->readonly);
852 : 0 : pfree(state->lowkey);
853 : 0 : state->lowkey = NULL;
854 : : }
855 : :
856 : : /* Don't change context for caller */
3103 andres@anarazel.de 857 :CBC 2480 : MemoryContextSwitchTo(oldcontext);
858 : :
859 : 2480 : return nextleveldown;
860 : : }
861 : :
862 : : /* Check visibility of the table entry referenced by nbtree index */
863 : : static bool
679 akorotkov@postgresql 864 : 376 : heap_entry_is_visible(BtreeCheckState *state, ItemPointer tid)
865 : : {
866 : : bool tid_visible;
867 : :
868 : 376 : TupleTableSlot *slot = table_slot_create(state->heaprel, NULL);
869 : :
870 : 376 : tid_visible = table_tuple_fetch_row_version(state->heaprel,
871 : : tid, state->snapshot, slot);
872 [ + - ]: 376 : if (slot != NULL)
873 : 376 : ExecDropSingleTupleTableSlot(slot);
874 : :
875 : 376 : return tid_visible;
876 : : }
877 : :
878 : : /*
879 : : * Prepare an error message for unique constrain violation in
880 : : * a btree index and report ERROR.
881 : : */
882 : : static void
883 : 3 : bt_report_duplicate(BtreeCheckState *state,
884 : : BtreeLastVisibleEntry *lVis,
885 : : ItemPointer nexttid, BlockNumber nblock, OffsetNumber noffset,
886 : : int nposting)
887 : : {
888 : : char *htid,
889 : : *nhtid,
890 : : *itid,
891 : 3 : *nitid = "",
892 : 3 : *pposting = "",
893 : 3 : *pnposting = "";
894 : :
895 : 3 : htid = psprintf("tid=(%u,%u)",
471 896 : 3 : ItemPointerGetBlockNumberNoCheck(lVis->tid),
897 : 3 : ItemPointerGetOffsetNumberNoCheck(lVis->tid));
679 898 : 3 : nhtid = psprintf("tid=(%u,%u)",
899 : : ItemPointerGetBlockNumberNoCheck(nexttid),
900 : 3 : ItemPointerGetOffsetNumberNoCheck(nexttid));
471 901 : 3 : itid = psprintf("tid=(%u,%u)", lVis->blkno, lVis->offset);
902 : :
903 [ + - + - ]: 3 : if (nblock != lVis->blkno || noffset != lVis->offset)
679 904 : 3 : nitid = psprintf(" tid=(%u,%u)", nblock, noffset);
905 : :
471 906 [ - + ]: 3 : if (lVis->postingIndex >= 0)
471 akorotkov@postgresql 907 :UBC 0 : pposting = psprintf(" posting %u", lVis->postingIndex);
908 : :
679 akorotkov@postgresql 909 [ - + ]:CBC 3 : if (nposting >= 0)
679 akorotkov@postgresql 910 :UBC 0 : pnposting = psprintf(" posting %u", nposting);
911 : :
679 akorotkov@postgresql 912 [ + - ]:CBC 3 : ereport(ERROR,
913 : : (errcode(ERRCODE_INDEX_CORRUPTED),
914 : : errmsg("index uniqueness is violated for index \"%s\"",
915 : : RelationGetRelationName(state->rel)),
916 : : errdetail("Index %s%s and%s%s (point to heap %s and %s) page lsn=%X/%08X.",
917 : : itid, pposting, nitid, pnposting, htid, nhtid,
918 : : LSN_FORMAT_ARGS(state->targetlsn))));
919 : : }
920 : :
921 : : /* Check if current nbtree leaf entry complies with UNIQUE constraint */
922 : : static void
923 : 360 : bt_entry_unique_check(BtreeCheckState *state, IndexTuple itup,
924 : : BlockNumber targetblock, OffsetNumber offset,
925 : : BtreeLastVisibleEntry *lVis)
926 : : {
927 : : ItemPointer tid;
928 : 360 : bool has_visible_entry = false;
929 : :
930 [ - + ]: 360 : Assert(targetblock != P_NONE);
931 : :
932 : : /*
933 : : * Current tuple has posting list. Report duplicate if TID of any posting
934 : : * list entry is visible and lVis->tid is valid.
935 : : */
936 [ + + ]: 360 : if (BTreeTupleIsPosting(itup))
937 : : {
679 akorotkov@postgresql 938 [ + + ]:GBC 48 : for (int i = 0; i < BTreeTupleGetNPosting(itup); i++)
939 : : {
940 : 32 : tid = BTreeTupleGetPostingN(itup, i);
941 [ + + ]: 32 : if (heap_entry_is_visible(state, tid))
942 : : {
943 : 16 : has_visible_entry = true;
471 944 [ - + ]: 16 : if (ItemPointerIsValid(lVis->tid))
945 : : {
679 akorotkov@postgresql 946 :UBC 0 : bt_report_duplicate(state,
947 : : lVis,
948 : : tid, targetblock,
949 : : offset, i);
950 : : }
951 : :
952 : : /*
953 : : * Prevent double reporting unique constraint violation
954 : : * between the posting list entries of the first tuple on the
955 : : * page after cross-page check.
956 : : */
471 akorotkov@postgresql 957 [ + - - + ]:GBC 16 : if (lVis->blkno != targetblock && ItemPointerIsValid(lVis->tid))
679 akorotkov@postgresql 958 :UBC 0 : return;
959 : :
471 akorotkov@postgresql 960 :GBC 16 : lVis->blkno = targetblock;
961 : 16 : lVis->offset = offset;
962 : 16 : lVis->postingIndex = i;
963 : 16 : lVis->tid = tid;
964 : : }
965 : : }
966 : : }
967 : :
968 : : /*
969 : : * Current tuple has no posting list. If TID is visible save info about it
970 : : * for the next comparisons in the loop in bt_target_page_check(). Report
971 : : * duplicate if lVis->tid is already valid.
972 : : */
973 : : else
974 : : {
679 akorotkov@postgresql 975 :CBC 344 : tid = BTreeTupleGetHeapTID(itup);
976 [ + + ]: 344 : if (heap_entry_is_visible(state, tid))
977 : : {
978 : 15 : has_visible_entry = true;
471 979 [ + + ]: 15 : if (ItemPointerIsValid(lVis->tid))
980 : : {
679 981 : 3 : bt_report_duplicate(state,
982 : : lVis,
983 : : tid, targetblock,
984 : : offset, -1);
985 : : }
986 : :
471 987 : 12 : lVis->blkno = targetblock;
988 : 12 : lVis->offset = offset;
989 : 12 : lVis->tid = tid;
990 : 12 : lVis->postingIndex = -1;
991 : : }
992 : : }
993 : :
994 [ + + ]: 357 : if (!has_visible_entry &&
995 [ + + ]: 329 : lVis->blkno != InvalidBlockNumber &&
996 [ - + ]: 9 : lVis->blkno != targetblock)
997 : : {
679 akorotkov@postgresql 998 :UBC 0 : char *posting = "";
999 : :
471 1000 [ # # ]: 0 : if (lVis->postingIndex >= 0)
1001 : 0 : posting = psprintf(" posting %u", lVis->postingIndex);
679 1002 [ # # ]: 0 : ereport(DEBUG1,
1003 : : (errcode(ERRCODE_NO_DATA),
1004 : : errmsg("index uniqueness can not be checked for index tid=(%u,%u) in index \"%s\"",
1005 : : targetblock, offset,
1006 : : RelationGetRelationName(state->rel)),
1007 : : errdetail("It doesn't have visible heap tids and key is equal to the tid=(%u,%u)%s (points to heap tid=(%u,%u)).",
1008 : : lVis->blkno, lVis->offset, posting,
1009 : : ItemPointerGetBlockNumberNoCheck(lVis->tid),
1010 : : ItemPointerGetOffsetNumberNoCheck(lVis->tid)),
1011 : : errhint("VACUUM the table and repeat the check.")));
1012 : : }
1013 : : }
1014 : :
1015 : : /*
1016 : : * Like P_LEFTMOST(start_opaque), but accept an arbitrarily-long chain of
1017 : : * half-dead, sibling-linked pages to the left. If a half-dead page appears
1018 : : * under state->readonly, the database exited recovery between the first-stage
1019 : : * and second-stage WAL records of a deletion.
1020 : : */
1021 : : static bool
677 noah@leadboat.com 1022 :CBC 55 : bt_leftmost_ignoring_half_dead(BtreeCheckState *state,
1023 : : BlockNumber start,
1024 : : BTPageOpaque start_opaque)
1025 : : {
1026 : 55 : BlockNumber reached = start_opaque->btpo_prev,
1027 : 55 : reached_from = start;
1028 : 55 : bool all_half_dead = true;
1029 : :
1030 : : /*
1031 : : * To handle the !readonly case, we'd need to accept BTP_DELETED pages and
1032 : : * potentially observe nbtree/README "Page deletion and backwards scans".
1033 : : */
1034 [ - + ]: 55 : Assert(state->readonly);
1035 : :
1036 [ + + + - ]: 57 : while (reached != P_NONE && all_half_dead)
1037 : : {
1038 : 2 : Page page = palloc_btree_page(state, reached);
1039 : 2 : BTPageOpaque reached_opaque = BTPageGetOpaque(page);
1040 : :
1041 [ - + ]: 2 : CHECK_FOR_INTERRUPTS();
1042 : :
1043 : : /*
1044 : : * Try to detect btpo_prev circular links. _bt_unlink_halfdead_page()
1045 : : * writes that side-links will continue to point to the siblings.
1046 : : * Check btpo_next for that property.
1047 : : */
1048 [ + - ]: 2 : all_half_dead = P_ISHALFDEAD(reached_opaque) &&
1049 [ + - ]: 2 : reached != start &&
1050 [ + - ]: 4 : reached != reached_from &&
1051 [ + - ]: 2 : reached_opaque->btpo_next == reached_from;
1052 [ + - ]: 2 : if (all_half_dead)
1053 : : {
1054 : 2 : XLogRecPtr pagelsn = PageGetLSN(page);
1055 : :
1056 : : /* pagelsn should point to an XLOG_BTREE_MARK_PAGE_HALFDEAD */
1057 [ + - ]: 2 : ereport(DEBUG1,
1058 : : (errcode(ERRCODE_NO_DATA),
1059 : : errmsg_internal("harmless interrupted page deletion detected in index \"%s\"",
1060 : : RelationGetRelationName(state->rel)),
1061 : : errdetail_internal("Block=%u right block=%u page lsn=%X/%08X.",
1062 : : reached, reached_from,
1063 : : LSN_FORMAT_ARGS(pagelsn))));
1064 : :
1065 : 2 : reached_from = reached;
1066 : 2 : reached = reached_opaque->btpo_prev;
1067 : : }
1068 : :
1069 : 2 : pfree(page);
1070 : : }
1071 : :
1072 : 55 : return all_half_dead;
1073 : : }
1074 : :
1075 : : /*
1076 : : * Raise an error when target page's left link does not point back to the
1077 : : * previous target page, called leftcurrent here. The leftcurrent page's
1078 : : * right link was followed to get to the current target page, and we expect
1079 : : * mutual agreement among leftcurrent and the current target page. Make sure
1080 : : * that this condition has definitely been violated in the !readonly case,
1081 : : * where concurrent page splits are something that we need to deal with.
1082 : : *
1083 : : * Cross-page inconsistencies involving pages that don't agree about being
1084 : : * siblings are known to be a particularly good indicator of corruption
1085 : : * involving partial writes/lost updates. The bt_right_page_check_scankey
1086 : : * check also provides a way of detecting cross-page inconsistencies for
1087 : : * !readonly callers, but it can only detect sibling pages that have an
1088 : : * out-of-order keyspace, which can't catch many of the problems that we
1089 : : * expect to catch here.
1090 : : *
1091 : : * The classic example of the kind of inconsistency that we can only catch
1092 : : * with this check (when in !readonly mode) involves three sibling pages that
1093 : : * were affected by a faulty page split at some point in the past. The
1094 : : * effects of the split are reflected in the original page and its new right
1095 : : * sibling page, with a lack of any accompanying changes for the _original_
1096 : : * right sibling page. The original right sibling page's left link fails to
1097 : : * point to the new right sibling page (its left link still points to the
1098 : : * original page), even though the first phase of a page split is supposed to
1099 : : * work as a single atomic action. This subtle inconsistency will probably
1100 : : * only break backwards scans in practice.
1101 : : *
1102 : : * Note that this is the only place where amcheck will "couple" buffer locks
1103 : : * (and only for !readonly callers). In general we prefer to avoid more
1104 : : * thorough cross-page checks in !readonly mode, but it seems worth the
1105 : : * complexity here. Also, the performance overhead of performing lock
1106 : : * coupling here is negligible in practice. Control only reaches here with a
1107 : : * non-corrupt index when there is a concurrent page split at the instant
1108 : : * caller crossed over to target page from leftcurrent page.
1109 : : */
1110 : : static void
1855 pg@bowt.ie 1111 :UBC 0 : bt_recheck_sibling_links(BtreeCheckState *state,
1112 : : BlockNumber btpo_prev_from_target,
1113 : : BlockNumber leftcurrent)
1114 : : {
1115 : : /* passing metapage to BTPageGetOpaque() would give irrelevant findings */
677 noah@leadboat.com 1116 [ # # ]: 0 : Assert(leftcurrent != P_NONE);
1117 : :
1855 pg@bowt.ie 1118 [ # # ]: 0 : if (!state->readonly)
1119 : : {
1120 : : Buffer lbuf;
1121 : : Buffer newtargetbuf;
1122 : : Page page;
1123 : : BTPageOpaque opaque;
1124 : : BlockNumber newtargetblock;
1125 : :
1126 : : /* Couple locks in the usual order for nbtree: Left to right */
1127 : 0 : lbuf = ReadBufferExtended(state->rel, MAIN_FORKNUM, leftcurrent,
1128 : : RBM_NORMAL, state->checkstrategy);
1129 : 0 : LockBuffer(lbuf, BT_READ);
1130 : 0 : _bt_checkpage(state->rel, lbuf);
1131 : 0 : page = BufferGetPage(lbuf);
1254 michael@paquier.xyz 1132 : 0 : opaque = BTPageGetOpaque(page);
1855 pg@bowt.ie 1133 [ # # ]: 0 : if (P_ISDELETED(opaque))
1134 : : {
1135 : : /*
1136 : : * Cannot reason about concurrently deleted page -- the left link
1137 : : * in the page to the right is expected to point to some other
1138 : : * page to the left (not leftcurrent page).
1139 : : *
1140 : : * Note that we deliberately don't give up with a half-dead page.
1141 : : */
1142 : 0 : UnlockReleaseBuffer(lbuf);
1143 : 0 : return;
1144 : : }
1145 : :
1146 : 0 : newtargetblock = opaque->btpo_next;
1147 : : /* Avoid self-deadlock when newtargetblock == leftcurrent */
1148 [ # # ]: 0 : if (newtargetblock != leftcurrent)
1149 : : {
1150 : 0 : newtargetbuf = ReadBufferExtended(state->rel, MAIN_FORKNUM,
1151 : : newtargetblock, RBM_NORMAL,
1152 : : state->checkstrategy);
1153 : 0 : LockBuffer(newtargetbuf, BT_READ);
1154 : 0 : _bt_checkpage(state->rel, newtargetbuf);
1155 : 0 : page = BufferGetPage(newtargetbuf);
1254 michael@paquier.xyz 1156 : 0 : opaque = BTPageGetOpaque(page);
1157 : : /* btpo_prev_from_target may have changed; update it */
1855 pg@bowt.ie 1158 : 0 : btpo_prev_from_target = opaque->btpo_prev;
1159 : : }
1160 : : else
1161 : : {
1162 : : /*
1163 : : * leftcurrent right sibling points back to leftcurrent block.
1164 : : * Index is corrupt. Easiest way to handle this is to pretend
1165 : : * that we actually read from a distinct page that has an invalid
1166 : : * block number in its btpo_prev.
1167 : : */
1168 : 0 : newtargetbuf = InvalidBuffer;
1169 : 0 : btpo_prev_from_target = InvalidBlockNumber;
1170 : : }
1171 : :
1172 : : /*
1173 : : * No need to check P_ISDELETED here, since new target block cannot be
1174 : : * marked deleted as long as we hold a lock on lbuf
1175 : : */
1176 [ # # ]: 0 : if (BufferIsValid(newtargetbuf))
1177 : 0 : UnlockReleaseBuffer(newtargetbuf);
1178 : 0 : UnlockReleaseBuffer(lbuf);
1179 : :
1180 [ # # ]: 0 : if (btpo_prev_from_target == leftcurrent)
1181 : : {
1182 : : /* Report split in left sibling, not target (or new target) */
1183 [ # # ]: 0 : ereport(DEBUG1,
1184 : : (errcode(ERRCODE_INTERNAL_ERROR),
1185 : : errmsg_internal("harmless concurrent page split detected in index \"%s\"",
1186 : : RelationGetRelationName(state->rel)),
1187 : : errdetail_internal("Block=%u new right sibling=%u original right sibling=%u.",
1188 : : leftcurrent, newtargetblock,
1189 : : state->targetblock)));
1190 : 0 : return;
1191 : : }
1192 : :
1193 : : /*
1194 : : * Index is corrupt. Make sure that we report correct target page.
1195 : : *
1196 : : * This could have changed in cases where there was a concurrent page
1197 : : * split, as well as index corruption (at least in theory). Note that
1198 : : * btpo_prev_from_target was already updated above.
1199 : : */
1200 : 0 : state->targetblock = newtargetblock;
1201 : : }
1202 : :
1203 [ # # ]: 0 : ereport(ERROR,
1204 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1205 : : errmsg("left link/right link pair in index \"%s\" not in agreement",
1206 : : RelationGetRelationName(state->rel)),
1207 : : errdetail_internal("Block=%u left block=%u left link from block=%u.",
1208 : : state->targetblock, leftcurrent,
1209 : : btpo_prev_from_target)));
1210 : : }
1211 : :
1212 : : /*
1213 : : * Function performs the following checks on target page, or pages ancillary to
1214 : : * target page:
1215 : : *
1216 : : * - That every "real" data item is less than or equal to the high key, which
1217 : : * is an upper bound on the items on the page. Data items should be
1218 : : * strictly less than the high key when the page is an internal page.
1219 : : *
1220 : : * - That within the page, every data item is strictly less than the item
1221 : : * immediately to its right, if any (i.e., that the items are in order
1222 : : * within the page, so that the binary searches performed by index scans are
1223 : : * sane).
1224 : : *
1225 : : * - That the last data item stored on the page is strictly less than the
1226 : : * first data item on the page to the right (when such a first item is
1227 : : * available).
1228 : : *
1229 : : * - Various checks on the structure of tuples themselves. For example, check
1230 : : * that non-pivot tuples have no truncated attributes.
1231 : : *
1232 : : * - For index with unique constraint make sure that only one of table entries
1233 : : * for equal keys is visible.
1234 : : *
1235 : : * Furthermore, when state passed shows ShareLock held, function also checks:
1236 : : *
1237 : : * - That all child pages respect strict lower bound from parent's pivot
1238 : : * tuple.
1239 : : *
1240 : : * - That downlink to block was encountered in parent where that's expected.
1241 : : *
1242 : : * - That high keys of child pages matches corresponding pivot keys in parent.
1243 : : *
1244 : : * This is also where heapallindexed callers use their Bloom filter to
1245 : : * fingerprint IndexTuples for later table_index_build_scan() verification.
1246 : : *
1247 : : * Note: Memory allocated in this routine is expected to be released by caller
1248 : : * resetting state->targetcontext.
1249 : : */
1250 : : static void
3103 andres@anarazel.de 1251 :CBC 9289 : bt_target_page_check(BtreeCheckState *state)
1252 : : {
1253 : : OffsetNumber offset;
1254 : : OffsetNumber max;
1255 : : BTPageOpaque topaque;
1256 : :
1257 : : /* Last visible entry info for checking indexes with unique constraint */
471 akorotkov@postgresql 1258 : 9289 : BtreeLastVisibleEntry lVis = {InvalidBlockNumber, InvalidOffsetNumber, -1, NULL};
1259 : :
1254 michael@paquier.xyz 1260 : 9289 : topaque = BTPageGetOpaque(state->target);
3103 andres@anarazel.de 1261 : 9289 : max = PageGetMaxOffsetNumber(state->target);
1262 : :
1263 [ - + - - ]: 9289 : elog(DEBUG2, "verifying %u items on %s block %u", max,
1264 : : P_ISLEAF(topaque) ? "leaf" : "internal", state->targetblock);
1265 : :
1266 : : /*
1267 : : * Check the number of attributes in high key. Note, rightmost page
1268 : : * doesn't contain a high key, so nothing to check
1269 : : */
2326 pg@bowt.ie 1270 [ + + ]: 9289 : if (!P_RIGHTMOST(topaque))
1271 : : {
1272 : : ItemId itemid;
1273 : : IndexTuple itup;
1274 : :
1275 : : /* Verify line pointer before checking tuple */
1276 : 6807 : itemid = PageGetItemIdCareful(state, state->targetblock,
1277 : : state->target, P_HIKEY);
1278 [ - + ]: 6807 : if (!_bt_check_natts(state->rel, state->heapkeyspace, state->target,
1279 : : P_HIKEY))
1280 : : {
2326 pg@bowt.ie 1281 :UBC 0 : itup = (IndexTuple) PageGetItem(state->target, itemid);
1282 [ # # # # : 0 : ereport(ERROR,
# # ]
1283 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1284 : : errmsg("wrong number of high key index tuple attributes in index \"%s\"",
1285 : : RelationGetRelationName(state->rel)),
1286 : : errdetail_internal("Index block=%u natts=%u block type=%s page lsn=%X/%08X.",
1287 : : state->targetblock,
1288 : : BTreeTupleGetNAtts(itup, state->rel),
1289 : : P_ISLEAF(topaque) ? "heap" : "index",
1290 : : LSN_FORMAT_ARGS(state->targetlsn))));
1291 : : }
1292 : : }
1293 : :
1294 : : /*
1295 : : * Loop over page items, starting from first non-highkey item, not high
1296 : : * key (if any). Most tests are not performed for the "negative infinity"
1297 : : * real item (if any).
1298 : : */
3103 andres@anarazel.de 1299 [ + + ]:CBC 9289 : for (offset = P_FIRSTDATAKEY(topaque);
1300 [ + + ]: 2062314 : offset <= max;
1301 : 2053025 : offset = OffsetNumberNext(offset))
1302 : : {
1303 : : ItemId itemid;
1304 : : IndexTuple itup;
1305 : : size_t tupsize;
1306 : : BTScanInsert skey;
1307 : : bool lowersizelimit;
1308 : : ItemPointer scantid;
1309 : :
1310 : : /*
1311 : : * True if we already called bt_entry_unique_check() for the current
1312 : : * item. This helps to avoid visiting the heap for keys, which are
1313 : : * anyway presented only once and can't comprise a unique violation.
1314 : : */
405 akorotkov@postgresql 1315 : 2053031 : bool unique_checked = false;
1316 : :
3103 andres@anarazel.de 1317 [ - + ]: 2053031 : CHECK_FOR_INTERRUPTS();
1318 : :
2326 pg@bowt.ie 1319 : 2053031 : itemid = PageGetItemIdCareful(state, state->targetblock,
1320 : : state->target, offset);
2716 andres@anarazel.de 1321 : 2053031 : itup = (IndexTuple) PageGetItem(state->target, itemid);
1322 : 2053031 : tupsize = IndexTupleSize(itup);
1323 : :
1324 : : /*
1325 : : * lp_len should match the IndexTuple reported length exactly, since
1326 : : * lp_len is completely redundant in indexes, and both sources of
1327 : : * tuple length are MAXALIGN()'d. nbtree does not use lp_len all that
1328 : : * frequently, and is surprisingly tolerant of corrupt lp_len fields.
1329 : : */
1330 [ - + ]: 2053031 : if (tupsize != ItemIdGetLength(itemid))
2716 andres@anarazel.de 1331 [ # # ]:UBC 0 : ereport(ERROR,
1332 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1333 : : errmsg("index tuple size does not equal lp_len in index \"%s\"",
1334 : : RelationGetRelationName(state->rel)),
1335 : : errdetail_internal("Index tid=(%u,%u) tuple size=%zu lp_len=%u page lsn=%X/%08X.",
1336 : : state->targetblock, offset,
1337 : : tupsize, ItemIdGetLength(itemid),
1338 : : LSN_FORMAT_ARGS(state->targetlsn)),
1339 : : errhint("This could be a torn page problem.")));
1340 : :
1341 : : /* Check the number of index tuple attributes */
2362 pg@bowt.ie 1342 [ - + ]:CBC 2053031 : if (!_bt_check_natts(state->rel, state->heapkeyspace, state->target,
1343 : : offset))
1344 : : {
1345 : : ItemPointer tid;
1346 : : char *itid,
1347 : : *htid;
1348 : :
2709 teodor@sigaev.ru 1349 :UBC 0 : itid = psprintf("(%u,%u)", state->targetblock, offset);
2019 pg@bowt.ie 1350 : 0 : tid = BTreeTupleGetPointsToTID(itup);
2709 teodor@sigaev.ru 1351 : 0 : htid = psprintf("(%u,%u)",
1352 : : ItemPointerGetBlockNumberNoCheck(tid),
2019 pg@bowt.ie 1353 : 0 : ItemPointerGetOffsetNumberNoCheck(tid));
1354 : :
2709 teodor@sigaev.ru 1355 [ # # # # : 0 : ereport(ERROR,
# # ]
1356 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1357 : : errmsg("wrong number of index tuple attributes in index \"%s\"",
1358 : : RelationGetRelationName(state->rel)),
1359 : : errdetail_internal("Index tid=%s natts=%u points to %s tid=%s page lsn=%X/%08X.",
1360 : : itid,
1361 : : BTreeTupleGetNAtts(itup, state->rel),
1362 : : P_ISLEAF(topaque) ? "heap" : "index",
1363 : : htid,
1364 : : LSN_FORMAT_ARGS(state->targetlsn))));
1365 : : }
1366 : :
1367 : : /*
1368 : : * Don't try to generate scankey using "negative infinity" item on
1369 : : * internal pages. They are always truncated to zero attributes.
1370 : : */
3103 andres@anarazel.de 1371 [ + + ]:CBC 2053031 : if (offset_is_negative_infinity(topaque, offset))
1372 : : {
1373 : : /*
1374 : : * We don't call bt_child_check() for "negative infinity" items.
1375 : : * But if we're performing downlink connectivity check, we do it
1376 : : * for every item including "negative infinity" one.
1377 : : */
2005 akorotkov@postgresql 1378 [ + - + + ]: 557 : if (!P_ISLEAF(topaque) && state->readonly)
1379 : : {
1380 : 12 : bt_child_highkey_check(state,
1381 : : offset,
1382 : : NULL,
1383 : : topaque->btpo_level);
1384 : : }
3103 andres@anarazel.de 1385 : 557 : continue;
1386 : : }
1387 : :
1388 : : /*
1389 : : * Readonly callers may optionally verify that non-pivot tuples can
1390 : : * each be found by an independent search that starts from the root.
1391 : : * Note that we deliberately don't do individual searches for each
1392 : : * TID, since the posting list itself is validated by other checks.
1393 : : */
2362 pg@bowt.ie 1394 [ + + + + ]: 2052474 : if (state->rootdescend && P_ISLEAF(topaque) &&
1395 [ - + ]: 201098 : !bt_rootdescend(state, itup))
1396 : : {
2019 pg@bowt.ie 1397 :UBC 0 : ItemPointer tid = BTreeTupleGetPointsToTID(itup);
1398 : : char *itid,
1399 : : *htid;
1400 : :
2362 1401 : 0 : itid = psprintf("(%u,%u)", state->targetblock, offset);
2019 1402 : 0 : htid = psprintf("(%u,%u)", ItemPointerGetBlockNumber(tid),
1403 : 0 : ItemPointerGetOffsetNumber(tid));
1404 : :
2362 1405 [ # # ]: 0 : ereport(ERROR,
1406 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1407 : : errmsg("could not find tuple using search from root page in index \"%s\"",
1408 : : RelationGetRelationName(state->rel)),
1409 : : errdetail_internal("Index tid=%s points to heap tid=%s page lsn=%X/%08X.",
1410 : : itid, htid,
1411 : : LSN_FORMAT_ARGS(state->targetlsn))));
1412 : : }
1413 : :
1414 : : /*
1415 : : * If tuple is a posting list tuple, make sure posting list TIDs are
1416 : : * in order
1417 : : */
2019 pg@bowt.ie 1418 [ + + ]:CBC 2052474 : if (BTreeTupleIsPosting(itup))
1419 : : {
1420 : : ItemPointerData last;
1421 : : ItemPointer current;
1422 : :
1423 : 10951 : ItemPointerCopy(BTreeTupleGetHeapTID(itup), &last);
1424 : :
1425 [ + + ]: 78406 : for (int i = 1; i < BTreeTupleGetNPosting(itup); i++)
1426 : : {
1427 : :
1428 : 67455 : current = BTreeTupleGetPostingN(itup, i);
1429 : :
1430 [ - + ]: 67455 : if (ItemPointerCompare(current, &last) <= 0)
1431 : : {
2019 pg@bowt.ie 1432 :UBC 0 : char *itid = psprintf("(%u,%u)", state->targetblock, offset);
1433 : :
1434 [ # # ]: 0 : ereport(ERROR,
1435 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1436 : : errmsg_internal("posting list contains misplaced TID in index \"%s\"",
1437 : : RelationGetRelationName(state->rel)),
1438 : : errdetail_internal("Index tid=%s posting list offset=%d page lsn=%X/%08X.",
1439 : : itid, i,
1440 : : LSN_FORMAT_ARGS(state->targetlsn))));
1441 : : }
1442 : :
2019 pg@bowt.ie 1443 :CBC 67455 : ItemPointerCopy(current, &last);
1444 : : }
1445 : : }
1446 : :
1447 : : /* Build insertion scankey for current page offset */
819 1448 : 2052474 : skey = bt_mkscankey_pivotsearch(state->rel, itup);
1449 : :
1450 : : /*
1451 : : * Make sure tuple size does not exceed the relevant BTREE_VERSION
1452 : : * specific limit.
1453 : : *
1454 : : * BTREE_VERSION 4 (which introduced heapkeyspace rules) requisitioned
1455 : : * a small amount of space from BTMaxItemSize() in order to ensure
1456 : : * that suffix truncation always has enough space to add an explicit
1457 : : * heap TID back to a tuple -- we pessimistically assume that every
1458 : : * newly inserted tuple will eventually need to have a heap TID
1459 : : * appended during a future leaf page split, when the tuple becomes
1460 : : * the basis of the new high key (pivot tuple) for the leaf page.
1461 : : *
1462 : : * Since the reclaimed space is reserved for that purpose, we must not
1463 : : * enforce the slightly lower limit when the extra space has been used
1464 : : * as intended. In other words, there is only a cross-version
1465 : : * difference in the limit on tuple size within leaf pages.
1466 : : *
1467 : : * Still, we're particular about the details within BTREE_VERSION 4
1468 : : * internal pages. Pivot tuples may only use the extra space for its
1469 : : * designated purpose. Enforce the lower limit for pivot tuples when
1470 : : * an explicit heap TID isn't actually present. (In all other cases
1471 : : * suffix truncation is guaranteed to generate a pivot tuple that's no
1472 : : * larger than the firstright tuple provided to it by its caller.)
1473 : : */
2362 1474 [ + - ]: 4104948 : lowersizelimit = skey->heapkeyspace &&
1475 [ + + + + ]: 2052474 : (P_ISLEAF(topaque) || BTreeTupleGetHeapTID(itup) == NULL);
179 1476 [ + + - + ]: 2052474 : if (tupsize > (lowersizelimit ? BTMaxItemSize : BTMaxItemSizeNoHeapTid))
1477 : : {
2019 pg@bowt.ie 1478 :UBC 0 : ItemPointer tid = BTreeTupleGetPointsToTID(itup);
1479 : : char *itid,
1480 : : *htid;
1481 : :
2362 1482 : 0 : itid = psprintf("(%u,%u)", state->targetblock, offset);
1483 : 0 : htid = psprintf("(%u,%u)",
1484 : : ItemPointerGetBlockNumberNoCheck(tid),
2019 1485 : 0 : ItemPointerGetOffsetNumberNoCheck(tid));
1486 : :
2362 1487 [ # # # # ]: 0 : ereport(ERROR,
1488 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1489 : : errmsg("index row size %zu exceeds maximum for index \"%s\"",
1490 : : tupsize, RelationGetRelationName(state->rel)),
1491 : : errdetail_internal("Index tid=%s points to %s tid=%s page lsn=%X/%08X.",
1492 : : itid,
1493 : : P_ISLEAF(topaque) ? "heap" : "index",
1494 : : htid,
1495 : : LSN_FORMAT_ARGS(state->targetlsn))));
1496 : : }
1497 : :
1498 : : /* Fingerprint leaf page tuples (those that point to the heap) */
2716 andres@anarazel.de 1499 [ + + + + :CBC 2052474 : if (state->heapallindexed && P_ISLEAF(topaque) && !ItemIdIsDead(itemid))
+ - ]
1500 : : {
1501 : : IndexTuple norm;
1502 : :
2019 pg@bowt.ie 1503 [ + + ]: 506953 : if (BTreeTupleIsPosting(itup))
1504 : : {
1505 : : /* Fingerprint all elements as distinct "plain" tuples */
1506 [ + + ]: 25697 : for (int i = 0; i < BTreeTupleGetNPosting(itup); i++)
1507 : : {
1508 : : IndexTuple logtuple;
1509 : :
1510 : 25523 : logtuple = bt_posting_plain_tuple(itup, i);
1511 : 25523 : norm = bt_normalize_tuple(state, logtuple);
1512 : 25523 : bloom_add_element(state->filter, (unsigned char *) norm,
1513 : : IndexTupleSize(norm));
1514 : : /* Be tidy */
1515 [ + + ]: 25523 : if (norm != logtuple)
1516 : 2 : pfree(norm);
1517 : 25523 : pfree(logtuple);
1518 : : }
1519 : : }
1520 : : else
1521 : : {
1522 : 506779 : norm = bt_normalize_tuple(state, itup);
1523 : 506779 : bloom_add_element(state->filter, (unsigned char *) norm,
1524 : : IndexTupleSize(norm));
1525 : : /* Be tidy */
1526 [ + + ]: 506779 : if (norm != itup)
1527 : 1 : pfree(norm);
1528 : : }
1529 : : }
1530 : :
1531 : : /*
1532 : : * * High key check *
1533 : : *
1534 : : * If there is a high key (if this is not the rightmost page on its
1535 : : * entire level), check that high key actually is upper bound on all
1536 : : * page items. If this is a posting list tuple, we'll need to set
1537 : : * scantid to be highest TID in posting list.
1538 : : *
1539 : : * We prefer to check all items against high key rather than checking
1540 : : * just the last and trusting that the operator class obeys the
1541 : : * transitive law (which implies that all previous items also
1542 : : * respected the high key invariant if they pass the item order
1543 : : * check).
1544 : : *
1545 : : * Ideally, we'd compare every item in the index against every other
1546 : : * item in the index, and not trust opclass obedience of the
1547 : : * transitive law to bridge the gap between children and their
1548 : : * grandparents (as well as great-grandparents, and so on). We don't
1549 : : * go to those lengths because that would be prohibitively expensive,
1550 : : * and probably not markedly more effective in practice.
1551 : : *
1552 : : * On the leaf level, we check that the key is <= the highkey.
1553 : : * However, on non-leaf levels we check that the key is < the highkey,
1554 : : * because the high key is "just another separator" rather than a copy
1555 : : * of some existing key item; we expect it to be unique among all keys
1556 : : * on the same level. (Suffix truncation will sometimes produce a
1557 : : * leaf highkey that is an untruncated copy of the lastleft item, but
1558 : : * never any other item, which necessitates weakening the leaf level
1559 : : * check to <=.)
1560 : : *
1561 : : * Full explanation for why a highkey is never truly a copy of another
1562 : : * item from the same level on internal levels:
1563 : : *
1564 : : * While the new left page's high key is copied from the first offset
1565 : : * on the right page during an internal page split, that's not the
1566 : : * full story. In effect, internal pages are split in the middle of
1567 : : * the firstright tuple, not between the would-be lastleft and
1568 : : * firstright tuples: the firstright key ends up on the left side as
1569 : : * left's new highkey, and the firstright downlink ends up on the
1570 : : * right side as right's new "negative infinity" item. The negative
1571 : : * infinity tuple is truncated to zero attributes, so we're only left
1572 : : * with the downlink. In other words, the copying is just an
1573 : : * implementation detail of splitting in the middle of a (pivot)
1574 : : * tuple. (See also: "Notes About Data Representation" in the nbtree
1575 : : * README.)
1576 : : */
1577 : 2052474 : scantid = skey->scantid;
1578 [ + - + + ]: 2052474 : if (state->heapkeyspace && BTreeTupleIsPosting(itup))
1579 : 10951 : skey->scantid = BTreeTupleGetMaxHeapTID(itup);
1580 : :
3103 andres@anarazel.de 1581 [ + + - + ]: 3934677 : if (!P_RIGHTMOST(topaque) &&
2362 pg@bowt.ie 1582 [ + + ]: 1882203 : !(P_ISLEAF(topaque) ? invariant_leq_offset(state, skey, P_HIKEY) :
1583 : 566 : invariant_l_offset(state, skey, P_HIKEY)))
1584 : : {
2019 pg@bowt.ie 1585 :UBC 0 : ItemPointer tid = BTreeTupleGetPointsToTID(itup);
1586 : : char *itid,
1587 : : *htid;
1588 : :
3103 andres@anarazel.de 1589 : 0 : itid = psprintf("(%u,%u)", state->targetblock, offset);
1590 : 0 : htid = psprintf("(%u,%u)",
1591 : : ItemPointerGetBlockNumberNoCheck(tid),
2019 pg@bowt.ie 1592 : 0 : ItemPointerGetOffsetNumberNoCheck(tid));
1593 : :
3103 andres@anarazel.de 1594 [ # # # # ]: 0 : ereport(ERROR,
1595 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1596 : : errmsg("high key invariant violated for index \"%s\"",
1597 : : RelationGetRelationName(state->rel)),
1598 : : errdetail_internal("Index tid=%s points to %s tid=%s page lsn=%X/%08X.",
1599 : : itid,
1600 : : P_ISLEAF(topaque) ? "heap" : "index",
1601 : : htid,
1602 : : LSN_FORMAT_ARGS(state->targetlsn))));
1603 : : }
1604 : : /* Reset, in case scantid was set to (itup) posting tuple's max TID */
2019 pg@bowt.ie 1605 :CBC 2052474 : skey->scantid = scantid;
1606 : :
1607 : : /*
1608 : : * * Item order check *
1609 : : *
1610 : : * Check that items are stored on page in logical order, by checking
1611 : : * current item is strictly less than next item (if any).
1612 : : */
3103 andres@anarazel.de 1613 [ + + ]: 2052474 : if (OffsetNumberNext(offset) <= max &&
2362 pg@bowt.ie 1614 [ + + ]: 2043193 : !invariant_l_offset(state, skey, OffsetNumberNext(offset)))
1615 : : {
1616 : : ItemPointer tid;
1617 : : char *itid,
1618 : : *htid,
1619 : : *nitid,
1620 : : *nhtid;
1621 : :
3103 andres@anarazel.de 1622 : 3 : itid = psprintf("(%u,%u)", state->targetblock, offset);
2019 pg@bowt.ie 1623 : 3 : tid = BTreeTupleGetPointsToTID(itup);
3103 andres@anarazel.de 1624 : 3 : htid = psprintf("(%u,%u)",
1625 : : ItemPointerGetBlockNumberNoCheck(tid),
2019 pg@bowt.ie 1626 : 3 : ItemPointerGetOffsetNumberNoCheck(tid));
3103 andres@anarazel.de 1627 : 3 : nitid = psprintf("(%u,%u)", state->targetblock,
1628 : 3 : OffsetNumberNext(offset));
1629 : :
1630 : : /* Reuse itup to get pointed-to heap location of second item */
2326 pg@bowt.ie 1631 : 3 : itemid = PageGetItemIdCareful(state, state->targetblock,
1632 : : state->target,
1633 : 3 : OffsetNumberNext(offset));
3103 andres@anarazel.de 1634 : 3 : itup = (IndexTuple) PageGetItem(state->target, itemid);
2019 pg@bowt.ie 1635 : 3 : tid = BTreeTupleGetPointsToTID(itup);
3103 andres@anarazel.de 1636 : 3 : nhtid = psprintf("(%u,%u)",
1637 : : ItemPointerGetBlockNumberNoCheck(tid),
2019 pg@bowt.ie 1638 : 3 : ItemPointerGetOffsetNumberNoCheck(tid));
1639 : :
3103 andres@anarazel.de 1640 [ + - + + : 3 : ereport(ERROR,
+ + ]
1641 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1642 : : errmsg("item order invariant violated for index \"%s\"",
1643 : : RelationGetRelationName(state->rel)),
1644 : : errdetail_internal("Lower index tid=%s (points to %s tid=%s) higher index tid=%s (points to %s tid=%s) page lsn=%X/%08X.",
1645 : : itid,
1646 : : P_ISLEAF(topaque) ? "heap" : "index",
1647 : : htid,
1648 : : nitid,
1649 : : P_ISLEAF(topaque) ? "heap" : "index",
1650 : : nhtid,
1651 : : LSN_FORMAT_ARGS(state->targetlsn))));
1652 : : }
1653 : :
1654 : : /*
1655 : : * If the index is unique verify entries uniqueness by checking the
1656 : : * heap tuples visibility. Immediately check posting tuples and
1657 : : * tuples with repeated keys. Postpone check for keys, which have the
1658 : : * first appearance.
1659 : : */
679 akorotkov@postgresql 1660 [ + + + + ]: 2052471 : if (state->checkunique && state->indexinfo->ii_Unique &&
405 1661 [ + + + + : 300615 : P_ISLEAF(topaque) && !skey->anynullkeys &&
+ + ]
1662 [ + + ]: 299968 : (BTreeTupleIsPosting(itup) || ItemPointerIsValid(lVis.tid)))
1663 : : {
679 1664 : 28 : bt_entry_unique_check(state, itup, state->targetblock, offset,
1665 : : &lVis);
405 1666 : 25 : unique_checked = true;
1667 : : }
1668 : :
679 1669 [ + + + + ]: 2052468 : if (state->checkunique && state->indexinfo->ii_Unique &&
1670 [ + + + + ]: 150620 : P_ISLEAF(topaque) && OffsetNumberNext(offset) <= max)
1671 : : {
1672 : : /* Save current scankey tid */
1673 : 149232 : scantid = skey->scantid;
1674 : :
1675 : : /*
1676 : : * Invalidate scankey tid to make _bt_compare compare only keys in
1677 : : * the item to report equality even if heap TIDs are different
1678 : : */
1679 : 149232 : skey->scantid = NULL;
1680 : :
1681 : : /*
1682 : : * If next key tuple is different, invalidate last visible entry
1683 : : * data (whole index tuple or last posting in index tuple). Key
1684 : : * containing null value does not violate unique constraint and
1685 : : * treated as different to any other key.
1686 : : *
1687 : : * If the next key is the same as the previous one, do the
1688 : : * bt_entry_unique_check() call if it was postponed.
1689 : : */
1690 [ + + ]: 149232 : if (_bt_compare(state->rel, skey, state->target,
1691 [ + + ]: 149634 : OffsetNumberNext(offset)) != 0 || skey->anynullkeys)
1692 : : {
471 1693 : 148900 : lVis.blkno = InvalidBlockNumber;
1694 : 148900 : lVis.offset = InvalidOffsetNumber;
1695 : 148900 : lVis.postingIndex = -1;
1696 : 148900 : lVis.tid = NULL;
1697 : : }
405 1698 [ + - ]: 332 : else if (!unique_checked)
1699 : : {
1700 : 332 : bt_entry_unique_check(state, itup, state->targetblock, offset,
1701 : : &lVis);
1702 : : }
679 1703 : 149232 : skey->scantid = scantid; /* Restore saved scan key state */
1704 : : }
1705 : :
1706 : : /*
1707 : : * * Last item check *
1708 : : *
1709 : : * Check last item against next/right page's first data item's when
1710 : : * last item on page is reached. This additional check will detect
1711 : : * transposed pages iff the supposed right sibling page happens to
1712 : : * belong before target in the key space. (Otherwise, a subsequent
1713 : : * heap verification will probably detect the problem.)
1714 : : *
1715 : : * This check is similar to the item order check that will have
1716 : : * already been performed for every other "real" item on target page
1717 : : * when last item is checked. The difference is that the next item
1718 : : * (the item that is compared to target's last item) needs to come
1719 : : * from the next/sibling page. There may not be such an item
1720 : : * available from sibling for various reasons, though (e.g., target is
1721 : : * the rightmost page on level).
1722 : : */
1723 [ + + ]: 2052468 : if (offset == max)
1724 : : {
1725 : : BTScanInsert rightkey;
1726 : :
1727 : : /* first offset on a right index page (log only) */
1728 : 9281 : OffsetNumber rightfirstoffset = InvalidOffsetNumber;
1729 : :
1730 : : /* Get item in next/right page */
1731 : 9281 : rightkey = bt_right_page_check_scankey(state, &rightfirstoffset);
1732 : :
3103 andres@anarazel.de 1733 [ + + ]: 9281 : if (rightkey &&
2362 pg@bowt.ie 1734 [ - + ]: 6803 : !invariant_g_offset(state, rightkey, max))
1735 : : {
1736 : : /*
1737 : : * As explained at length in bt_right_page_check_scankey(),
1738 : : * there is a known !readonly race that could account for
1739 : : * apparent violation of invariant, which we must check for
1740 : : * before actually proceeding with raising error. Our canary
1741 : : * condition is that target page was deleted.
1742 : : */
3103 andres@anarazel.de 1743 [ # # ]:UBC 0 : if (!state->readonly)
1744 : : {
1745 : : /* Get fresh copy of target page */
1746 : 0 : state->target = palloc_btree_page(state, state->targetblock);
1747 : : /* Note that we deliberately do not update target LSN */
1254 michael@paquier.xyz 1748 : 0 : topaque = BTPageGetOpaque(state->target);
1749 : :
1750 : : /*
1751 : : * All !readonly checks now performed; just return
1752 : : */
3103 andres@anarazel.de 1753 [ # # ]: 0 : if (P_IGNORE(topaque))
1754 : 0 : return;
1755 : : }
1756 : :
1757 [ # # ]: 0 : ereport(ERROR,
1758 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1759 : : errmsg("cross page item order invariant violated for index \"%s\"",
1760 : : RelationGetRelationName(state->rel)),
1761 : : errdetail_internal("Last item on page tid=(%u,%u) page lsn=%X/%08X.",
1762 : : state->targetblock, offset,
1763 : : LSN_FORMAT_ARGS(state->targetlsn))));
1764 : : }
1765 : :
1766 : : /*
1767 : : * If index has unique constraint make sure that no more than one
1768 : : * found equal items is visible.
1769 : : */
679 akorotkov@postgresql 1770 [ + + + + :CBC 9281 : if (state->checkunique && state->indexinfo->ii_Unique &&
+ + ]
471 1771 [ + - + - ]: 549 : rightkey && P_ISLEAF(topaque) && !P_RIGHTMOST(topaque))
1772 : : {
1773 : 549 : BlockNumber rightblock_number = topaque->btpo_next;
1774 : :
679 1775 [ - + ]: 549 : elog(DEBUG2, "check cross page unique condition");
1776 : :
1777 : : /*
1778 : : * Make _bt_compare compare only index keys without heap TIDs.
1779 : : * rightkey->scantid is modified destructively but it is ok
1780 : : * for it is not used later.
1781 : : */
1782 : 549 : rightkey->scantid = NULL;
1783 : :
1784 : : /* The first key on the next page is the same */
405 1785 [ + + ]: 549 : if (_bt_compare(state->rel, rightkey, state->target, max) == 0 &&
1786 [ - + ]: 7 : !rightkey->anynullkeys)
1787 : : {
1788 : : Page rightpage;
1789 : :
1790 : : /*
1791 : : * Do the bt_entry_unique_check() call if it was
1792 : : * postponed.
1793 : : */
405 akorotkov@postgresql 1794 [ # # ]:UBC 0 : if (!unique_checked)
1795 : 0 : bt_entry_unique_check(state, itup, state->targetblock,
1796 : : offset, &lVis);
1797 : :
679 1798 [ # # ]: 0 : elog(DEBUG2, "cross page equal keys");
471 1799 : 0 : rightpage = palloc_btree_page(state,
1800 : : rightblock_number);
1801 : 0 : topaque = BTPageGetOpaque(rightpage);
1802 : :
1803 [ # # ]: 0 : if (P_IGNORE(topaque))
1804 : : {
468 1805 : 0 : pfree(rightpage);
1806 : 0 : break;
1807 : : }
1808 : :
1809 [ # # ]: 0 : if (unlikely(!P_ISLEAF(topaque)))
1810 [ # # ]: 0 : ereport(ERROR,
1811 : : (errcode(ERRCODE_INDEX_CORRUPTED),
1812 : : errmsg("right block of leaf block is non-leaf for index \"%s\"",
1813 : : RelationGetRelationName(state->rel)),
1814 : : errdetail_internal("Block=%u page lsn=%X/%08X.",
1815 : : state->targetblock,
1816 : : LSN_FORMAT_ARGS(state->targetlsn))));
1817 : :
679 1818 : 0 : itemid = PageGetItemIdCareful(state, rightblock_number,
1819 : : rightpage,
1820 : : rightfirstoffset);
471 1821 : 0 : itup = (IndexTuple) PageGetItem(rightpage, itemid);
1822 : :
1823 : 0 : bt_entry_unique_check(state, itup, rightblock_number, rightfirstoffset, &lVis);
1824 : :
1825 : 0 : pfree(rightpage);
1826 : : }
1827 : : }
1828 : : }
1829 : :
1830 : : /*
1831 : : * * Downlink check *
1832 : : *
1833 : : * Additional check of child items iff this is an internal page and
1834 : : * caller holds a ShareLock. This happens for every downlink (item)
1835 : : * in target excluding the negative-infinity downlink (again, this is
1836 : : * because it has no useful value to compare).
1837 : : */
3103 andres@anarazel.de 1838 [ + + + + ]:CBC 2052468 : if (!P_ISLEAF(topaque) && state->readonly)
2005 akorotkov@postgresql 1839 : 1861 : bt_child_check(state, skey, offset);
1840 : : }
1841 : :
1842 : : /*
1843 : : * Special case bt_child_highkey_check() call
1844 : : *
1845 : : * We don't pass a real downlink, but we've to finish the level
1846 : : * processing. If condition is satisfied, we've already processed all the
1847 : : * downlinks from the target level. But there still might be pages to the
1848 : : * right of the child page pointer to by our rightmost downlink. And they
1849 : : * might have missing downlinks. This final call checks for them.
1850 : : */
1851 [ + + + + : 9283 : if (!P_ISLEAF(topaque) && P_RIGHTMOST(topaque) && state->readonly)
+ + ]
1852 : : {
1853 : 11 : bt_child_highkey_check(state, InvalidOffsetNumber,
1854 : : NULL, topaque->btpo_level);
1855 : : }
1856 : : }
1857 : :
1858 : : /*
1859 : : * Return a scankey for an item on page to right of current target (or the
1860 : : * first non-ignorable page), sufficient to check ordering invariant on last
1861 : : * item in current target page. Returned scankey relies on local memory
1862 : : * allocated for the child page, which caller cannot pfree(). Caller's memory
1863 : : * context should be reset between calls here.
1864 : : *
1865 : : * This is the first data item, and so all adjacent items are checked against
1866 : : * their immediate sibling item (which may be on a sibling page, or even a
1867 : : * "cousin" page at parent boundaries where target's rightlink points to page
1868 : : * with different parent page). If no such valid item is available, return
1869 : : * NULL instead.
1870 : : *
1871 : : * Note that !readonly callers must reverify that target page has not
1872 : : * been concurrently deleted.
1873 : : *
1874 : : * Save rightfirstoffset for detailed error message.
1875 : : */
1876 : : static BTScanInsert
679 1877 : 9281 : bt_right_page_check_scankey(BtreeCheckState *state, OffsetNumber *rightfirstoffset)
1878 : : {
1879 : : BTPageOpaque opaque;
1880 : : ItemId rightitem;
1881 : : IndexTuple firstitup;
1882 : : BlockNumber targetnext;
1883 : : Page rightpage;
1884 : : OffsetNumber nline;
1885 : :
1886 : : /* Determine target's next block number */
1254 michael@paquier.xyz 1887 : 9281 : opaque = BTPageGetOpaque(state->target);
1888 : :
1889 : : /* If target is already rightmost, no right sibling; nothing to do here */
3103 andres@anarazel.de 1890 [ + + ]: 9281 : if (P_RIGHTMOST(opaque))
1891 : 2478 : return NULL;
1892 : :
1893 : : /*
1894 : : * General notes on concurrent page splits and page deletion:
1895 : : *
1896 : : * Routines like _bt_search() don't require *any* page split interlock
1897 : : * when descending the tree, including something very light like a buffer
1898 : : * pin. That's why it's okay that we don't either. This avoidance of any
1899 : : * need to "couple" buffer locks is the raison d' etre of the Lehman & Yao
1900 : : * algorithm, in fact.
1901 : : *
1902 : : * That leaves deletion. A deleted page won't actually be recycled by
1903 : : * VACUUM early enough for us to fail to at least follow its right link
1904 : : * (or left link, or downlink) and find its sibling, because recycling
1905 : : * does not occur until no possible index scan could land on the page.
1906 : : * Index scans can follow links with nothing more than their snapshot as
1907 : : * an interlock and be sure of at least that much. (See page
1908 : : * recycling/"visible to everyone" notes in nbtree README.)
1909 : : *
1910 : : * Furthermore, it's okay if we follow a rightlink and find a half-dead or
1911 : : * dead (ignorable) page one or more times. There will either be a
1912 : : * further right link to follow that leads to a live page before too long
1913 : : * (before passing by parent's rightmost child), or we will find the end
1914 : : * of the entire level instead (possible when parent page is itself the
1915 : : * rightmost on its level).
1916 : : */
1917 : 6803 : targetnext = opaque->btpo_next;
1918 : : for (;;)
1919 : : {
1920 [ - + ]: 6803 : CHECK_FOR_INTERRUPTS();
1921 : :
1922 : 6803 : rightpage = palloc_btree_page(state, targetnext);
1254 michael@paquier.xyz 1923 : 6803 : opaque = BTPageGetOpaque(rightpage);
1924 : :
3103 andres@anarazel.de 1925 [ - + - - ]: 6803 : if (!P_IGNORE(opaque) || P_RIGHTMOST(opaque))
1926 : : break;
1927 : :
1928 : : /*
1929 : : * We landed on a deleted or half-dead sibling page. Step right until
1930 : : * we locate a live sibling page.
1931 : : */
1635 pg@bowt.ie 1932 [ # # ]:UBC 0 : ereport(DEBUG2,
1933 : : (errcode(ERRCODE_NO_DATA),
1934 : : errmsg_internal("level %u sibling page in block %u of index \"%s\" was found deleted or half dead",
1935 : : opaque->btpo_level, targetnext, RelationGetRelationName(state->rel)),
1936 : : errdetail_internal("Deleted page found when building scankey from right sibling.")));
1937 : :
1938 : 0 : targetnext = opaque->btpo_next;
1939 : :
1940 : : /* Be slightly more pro-active in freeing this memory, just in case */
3103 andres@anarazel.de 1941 : 0 : pfree(rightpage);
1942 : : }
1943 : :
1944 : : /*
1945 : : * No ShareLock held case -- why it's safe to proceed.
1946 : : *
1947 : : * Problem:
1948 : : *
1949 : : * We must avoid false positive reports of corruption when caller treats
1950 : : * item returned here as an upper bound on target's last item. In
1951 : : * general, false positives are disallowed. Avoiding them here when
1952 : : * caller is !readonly is subtle.
1953 : : *
1954 : : * A concurrent page deletion by VACUUM of the target page can result in
1955 : : * the insertion of items on to this right sibling page that would
1956 : : * previously have been inserted on our target page. There might have
1957 : : * been insertions that followed the target's downlink after it was made
1958 : : * to point to right sibling instead of target by page deletion's first
1959 : : * phase. The inserters insert items that would belong on target page.
1960 : : * This race is very tight, but it's possible. This is our only problem.
1961 : : *
1962 : : * Non-problems:
1963 : : *
1964 : : * We are not hindered by a concurrent page split of the target; we'll
1965 : : * never land on the second half of the page anyway. A concurrent split
1966 : : * of the right page will also not matter, because the first data item
1967 : : * remains the same within the left half, which we'll reliably land on. If
1968 : : * we had to skip over ignorable/deleted pages, it cannot matter because
1969 : : * their key space has already been atomically merged with the first
1970 : : * non-ignorable page we eventually find (doesn't matter whether the page
1971 : : * we eventually find is a true sibling or a cousin of target, which we go
1972 : : * into below).
1973 : : *
1974 : : * Solution:
1975 : : *
1976 : : * Caller knows that it should reverify that target is not ignorable
1977 : : * (half-dead or deleted) when cross-page sibling item comparison appears
1978 : : * to indicate corruption (invariant fails). This detects the single race
1979 : : * condition that exists for caller. This is correct because the
1980 : : * continued existence of target block as non-ignorable (not half-dead or
1981 : : * deleted) implies that target page was not merged into from the right by
1982 : : * deletion; the key space at or after target never moved left. Target's
1983 : : * parent either has the same downlink to target as before, or a <
1984 : : * downlink due to deletion at the left of target. Target either has the
1985 : : * same highkey as before, or a highkey < before when there is a page
1986 : : * split. (The rightmost concurrently-split-from-target-page page will
1987 : : * still have the same highkey as target was originally found to have,
1988 : : * which for our purposes is equivalent to target's highkey itself never
1989 : : * changing, since we reliably skip over
1990 : : * concurrently-split-from-target-page pages.)
1991 : : *
1992 : : * In simpler terms, we allow that the key space of the target may expand
1993 : : * left (the key space can move left on the left side of target only), but
1994 : : * the target key space cannot expand right and get ahead of us without
1995 : : * our detecting it. The key space of the target cannot shrink, unless it
1996 : : * shrinks to zero due to the deletion of the original page, our canary
1997 : : * condition. (To be very precise, we're a bit stricter than that because
1998 : : * it might just have been that the target page split and only the
1999 : : * original target page was deleted. We can be more strict, just not more
2000 : : * lax.)
2001 : : *
2002 : : * Top level tree walk caller moves on to next page (makes it the new
2003 : : * target) following recovery from this race. (cf. The rationale for
2004 : : * child/downlink verification needing a ShareLock within
2005 : : * bt_child_check(), where page deletion is also the main source of
2006 : : * trouble.)
2007 : : *
2008 : : * Note that it doesn't matter if right sibling page here is actually a
2009 : : * cousin page, because in order for the key space to be readjusted in a
2010 : : * way that causes us issues in next level up (guiding problematic
2011 : : * concurrent insertions to the cousin from the grandparent rather than to
2012 : : * the sibling from the parent), there'd have to be page deletion of
2013 : : * target's parent page (affecting target's parent's downlink in target's
2014 : : * grandparent page). Internal page deletion only occurs when there are
2015 : : * no child pages (they were all fully deleted), and caller is checking
2016 : : * that the target's parent has at least one non-deleted (so
2017 : : * non-ignorable) child: the target page. (Note that the first phase of
2018 : : * deletion atomically marks the page to be deleted half-dead/ignorable at
2019 : : * the same time downlink in its parent is removed, so caller will
2020 : : * definitely not fail to detect that this happened.)
2021 : : *
2022 : : * This trick is inspired by the method backward scans use for dealing
2023 : : * with concurrent page splits; concurrent page deletion is a problem that
2024 : : * similarly receives special consideration sometimes (it's possible that
2025 : : * the backwards scan will re-read its "original" block after failing to
2026 : : * find a right-link to it, having already moved in the opposite direction
2027 : : * (right/"forwards") a few times to try to locate one). Just like us,
2028 : : * that happens only to determine if there was a concurrent page deletion
2029 : : * of a reference page, and just like us if there was a page deletion of
2030 : : * that reference page it means we can move on from caring about the
2031 : : * reference page. See the nbtree README for a full description of how
2032 : : * that works.
2033 : : */
3103 andres@anarazel.de 2034 :CBC 6803 : nline = PageGetMaxOffsetNumber(rightpage);
2035 : :
2036 : : /*
2037 : : * Get first data item, if any
2038 : : */
2039 [ + + + + : 6803 : if (P_ISLEAF(opaque) && nline >= P_FIRSTDATAKEY(opaque))
+ - ]
2040 : : {
2041 : : /* Return first data item (if any) */
2326 pg@bowt.ie 2042 : 6801 : rightitem = PageGetItemIdCareful(state, targetnext, rightpage,
2043 [ + + ]: 6801 : P_FIRSTDATAKEY(opaque));
679 akorotkov@postgresql 2044 [ + + ]: 6801 : *rightfirstoffset = P_FIRSTDATAKEY(opaque);
2045 : : }
3103 andres@anarazel.de 2046 [ + - + - ]: 4 : else if (!P_ISLEAF(opaque) &&
2047 [ + - ]: 2 : nline >= OffsetNumberNext(P_FIRSTDATAKEY(opaque)))
2048 : : {
2049 : : /*
2050 : : * Return first item after the internal page's "negative infinity"
2051 : : * item
2052 : : */
2326 pg@bowt.ie 2053 : 2 : rightitem = PageGetItemIdCareful(state, targetnext, rightpage,
2054 [ + - ]: 2 : OffsetNumberNext(P_FIRSTDATAKEY(opaque)));
2055 : : }
2056 : : else
2057 : : {
2058 : : /*
2059 : : * No first item. Page is probably empty leaf page, but it's also
2060 : : * possible that it's an internal page with only a negative infinity
2061 : : * item.
2062 : : */
1635 pg@bowt.ie 2063 [ # # # # ]:UBC 0 : ereport(DEBUG2,
2064 : : (errcode(ERRCODE_NO_DATA),
2065 : : errmsg_internal("%s block %u of index \"%s\" has no first data item",
2066 : : P_ISLEAF(opaque) ? "leaf" : "internal", targetnext,
2067 : : RelationGetRelationName(state->rel))));
3103 andres@anarazel.de 2068 : 0 : return NULL;
2069 : : }
2070 : :
2071 : : /*
2072 : : * Return first real item scankey. Note that this relies on right page
2073 : : * memory remaining allocated.
2074 : : */
2362 pg@bowt.ie 2075 :CBC 6803 : firstitup = (IndexTuple) PageGetItem(rightpage, rightitem);
819 2076 : 6803 : return bt_mkscankey_pivotsearch(state->rel, firstitup);
2077 : : }
2078 : :
2079 : : /*
2080 : : * Check if two tuples are binary identical except the block number. So,
2081 : : * this function is capable to compare pivot keys on different levels.
2082 : : */
2083 : : static bool
1816 2084 : 1862 : bt_pivot_tuple_identical(bool heapkeyspace, IndexTuple itup1, IndexTuple itup2)
2085 : : {
2005 akorotkov@postgresql 2086 [ - + ]: 1862 : if (IndexTupleSize(itup1) != IndexTupleSize(itup2))
2005 akorotkov@postgresql 2087 :UBC 0 : return false;
2088 : :
1816 pg@bowt.ie 2089 [ + - ]:CBC 1862 : if (heapkeyspace)
2090 : : {
2091 : : /*
2092 : : * Offset number will contain important information in heapkeyspace
2093 : : * indexes: the number of attributes left in the pivot tuple following
2094 : : * suffix truncation. Don't skip over it (compare it too).
2095 : : */
2096 [ - + ]: 1862 : if (memcmp(&itup1->t_tid.ip_posid, &itup2->t_tid.ip_posid,
2097 : 1862 : IndexTupleSize(itup1) -
2098 : : offsetof(ItemPointerData, ip_posid)) != 0)
1816 pg@bowt.ie 2099 :UBC 0 : return false;
2100 : : }
2101 : : else
2102 : : {
2103 : : /*
2104 : : * Cannot rely on offset number field having consistent value across
2105 : : * levels on pg_upgrade'd !heapkeyspace indexes. Compare contents of
2106 : : * tuple starting from just after item pointer (i.e. after block
2107 : : * number and offset number).
2108 : : */
2109 [ # # ]: 0 : if (memcmp(&itup1->t_info, &itup2->t_info,
2110 : 0 : IndexTupleSize(itup1) -
2111 : : offsetof(IndexTupleData, t_info)) != 0)
2112 : 0 : return false;
2113 : : }
2114 : :
2005 akorotkov@postgresql 2115 :CBC 1862 : return true;
2116 : : }
2117 : :
2118 : : /*---
2119 : : * Check high keys on the child level. Traverse rightlinks from previous
2120 : : * downlink to the current one. Check that there are no intermediate pages
2121 : : * with missing downlinks.
2122 : : *
2123 : : * If 'loaded_child' is given, it's assumed to be the page pointed to by the
2124 : : * downlink referenced by 'downlinkoffnum' of the target page.
2125 : : *
2126 : : * Basically this function is called for each target downlink and checks two
2127 : : * invariants:
2128 : : *
2129 : : * 1) You can reach the next child from previous one via rightlinks;
2130 : : * 2) Each child high key have matching pivot key on target level.
2131 : : *
2132 : : * Consider the sample tree picture.
2133 : : *
2134 : : * 1
2135 : : * / \
2136 : : * 2 <-> 3
2137 : : * / \ / \
2138 : : * 4 <> 5 <> 6 <> 7 <> 8
2139 : : *
2140 : : * This function will be called for blocks 4, 5, 6 and 8. Consider what is
2141 : : * happening for each function call.
2142 : : *
2143 : : * - The function call for block 4 initializes data structure and matches high
2144 : : * key of block 4 to downlink's pivot key of block 2.
2145 : : * - The high key of block 5 is matched to the high key of block 2.
2146 : : * - The block 6 has an incomplete split flag set, so its high key isn't
2147 : : * matched to anything.
2148 : : * - The function call for block 8 checks that block 8 can be found while
2149 : : * following rightlinks from block 6. The high key of block 7 will be
2150 : : * matched to downlink's pivot key in block 3.
2151 : : *
2152 : : * There is also final call of this function, which checks that there is no
2153 : : * missing downlinks for children to the right of the child referenced by
2154 : : * rightmost downlink in target level.
2155 : : */
2156 : : static void
2157 : 1884 : bt_child_highkey_check(BtreeCheckState *state,
2158 : : OffsetNumber target_downlinkoffnum,
2159 : : Page loaded_child,
2160 : : uint32 target_level)
2161 : : {
2162 : 1884 : BlockNumber blkno = state->prevrightlink;
2163 : : Page page;
2164 : : BTPageOpaque opaque;
2165 : 1884 : bool rightsplit = state->previncompletesplit;
2166 : 1884 : bool first = true;
2167 : : ItemId itemid;
2168 : : IndexTuple itup;
2169 : : BlockNumber downlink;
2170 : :
2171 [ + + + - : 1884 : if (OffsetNumberIsValid(target_downlinkoffnum))
+ + ]
2172 : : {
2173 : 1873 : itemid = PageGetItemIdCareful(state, state->targetblock,
2174 : : state->target, target_downlinkoffnum);
2175 : 1873 : itup = (IndexTuple) PageGetItem(state->target, itemid);
2176 : 1873 : downlink = BTreeTupleGetDownLink(itup);
2177 : : }
2178 : : else
2179 : : {
2180 : 11 : downlink = P_NONE;
2181 : : }
2182 : :
2183 : : /*
2184 : : * If no previous rightlink is memorized for current level just below
2185 : : * target page's level, we are about to start from the leftmost page. We
2186 : : * can't follow rightlinks from previous page, because there is no
2187 : : * previous page. But we still can match high key.
2188 : : *
2189 : : * So we initialize variables for the loop above like there is previous
2190 : : * page referencing current child. Also we imply previous page to not
2191 : : * have incomplete split flag, that would make us require downlink for
2192 : : * current child. That's correct, because leftmost page on the level
2193 : : * should always have parent downlink.
2194 : : */
2195 [ + + ]: 1884 : if (!BlockNumberIsValid(blkno))
2196 : : {
2197 : 11 : blkno = downlink;
2198 : 11 : rightsplit = false;
2199 : : }
2200 : :
2201 : : /* Move to the right on the child level */
2202 : : while (true)
2203 : : {
2204 : : /*
2205 : : * Did we traverse the whole tree level and this is check for pages to
2206 : : * the right of rightmost downlink?
2207 : : */
2208 [ + + + - ]: 1884 : if (blkno == P_NONE && downlink == P_NONE)
2209 : : {
2210 : 11 : state->prevrightlink = InvalidBlockNumber;
2211 : 11 : state->previncompletesplit = false;
2212 : 11 : return;
2213 : : }
2214 : :
2215 : : /* Did we traverse the whole tree level and don't find next downlink? */
2216 [ - + ]: 1873 : if (blkno == P_NONE)
2005 akorotkov@postgresql 2217 [ # # ]:UBC 0 : ereport(ERROR,
2218 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2219 : : errmsg("can't traverse from downlink %u to downlink %u of index \"%s\"",
2220 : : state->prevrightlink, downlink,
2221 : : RelationGetRelationName(state->rel))));
2222 : :
2223 : : /* Load page contents */
2005 akorotkov@postgresql 2224 [ + - + + ]:CBC 1873 : if (blkno == downlink && loaded_child)
2225 : 1861 : page = loaded_child;
2226 : : else
2227 : 12 : page = palloc_btree_page(state, blkno);
2228 : :
1254 michael@paquier.xyz 2229 : 1873 : opaque = BTPageGetOpaque(page);
2230 : :
2231 : : /* The first page we visit at the level should be leftmost */
677 noah@leadboat.com 2232 [ + - + + ]: 1873 : if (first && !BlockNumberIsValid(state->prevrightlink) &&
2233 [ - + ]: 11 : !bt_leftmost_ignoring_half_dead(state, blkno, opaque))
2005 akorotkov@postgresql 2234 [ # # ]:UBC 0 : ereport(ERROR,
2235 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2236 : : errmsg("the first child of leftmost target page is not leftmost of its level in index \"%s\"",
2237 : : RelationGetRelationName(state->rel)),
2238 : : errdetail_internal("Target block=%u child block=%u target page lsn=%X/%08X.",
2239 : : state->targetblock, blkno,
2240 : : LSN_FORMAT_ARGS(state->targetlsn))));
2241 : :
2242 : : /* Do level sanity check */
1655 pg@bowt.ie 2243 [ - + - - ]:CBC 1873 : if ((!P_ISDELETED(opaque) || P_HAS_FULLXID(opaque)) &&
2244 [ - + ]: 1873 : opaque->btpo_level != target_level - 1)
2005 akorotkov@postgresql 2245 [ # # ]:UBC 0 : ereport(ERROR,
2246 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2247 : : errmsg("block found while following rightlinks from child of index \"%s\" has invalid level",
2248 : : RelationGetRelationName(state->rel)),
2249 : : errdetail_internal("Block pointed to=%u expected level=%u level in pointed to block=%u.",
2250 : : blkno, target_level - 1, opaque->btpo_level)));
2251 : :
2252 : : /* Try to detect circular links */
2005 akorotkov@postgresql 2253 [ - + - - :CBC 1873 : if ((!first && blkno == state->prevrightlink) || blkno == opaque->btpo_prev)
- + ]
2005 akorotkov@postgresql 2254 [ # # ]:UBC 0 : ereport(ERROR,
2255 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2256 : : errmsg("circular link chain found in block %u of index \"%s\"",
2257 : : blkno, RelationGetRelationName(state->rel))));
2258 : :
2005 akorotkov@postgresql 2259 [ - + - - ]:CBC 1873 : if (blkno != downlink && !P_IGNORE(opaque))
2260 : : {
2261 : : /* blkno probably has missing parent downlink */
2005 akorotkov@postgresql 2262 :UBC 0 : bt_downlink_missing_check(state, rightsplit, blkno, page);
2263 : : }
2264 : :
2005 akorotkov@postgresql 2265 :CBC 1873 : rightsplit = P_INCOMPLETE_SPLIT(opaque);
2266 : :
2267 : : /*
2268 : : * If we visit page with high key, check that it is equal to the
2269 : : * target key next to corresponding downlink.
2270 : : */
2271 [ + - + + ]: 1873 : if (!rightsplit && !P_RIGHTMOST(opaque))
2272 : : {
2273 : : BTPageOpaque topaque;
2274 : : IndexTuple highkey;
2275 : : OffsetNumber pivotkey_offset;
2276 : :
2277 : : /* Get high key */
2278 : 1862 : itemid = PageGetItemIdCareful(state, blkno, page, P_HIKEY);
2279 : 1862 : highkey = (IndexTuple) PageGetItem(page, itemid);
2280 : :
2281 : : /*
2282 : : * There might be two situations when we examine high key. If
2283 : : * current child page is referenced by given target downlink, we
2284 : : * should look to the next offset number for matching key from
2285 : : * target page.
2286 : : *
2287 : : * Alternatively, we're following rightlinks somewhere in the
2288 : : * middle between page referenced by previous target's downlink
2289 : : * and the page referenced by current target's downlink. If
2290 : : * current child page hasn't incomplete split flag set, then its
2291 : : * high key should match to the target's key of current offset
2292 : : * number. This happens when a previous call here (to
2293 : : * bt_child_highkey_check()) found an incomplete split, and we
2294 : : * reach a right sibling page without a downlink -- the right
2295 : : * sibling page's high key still needs to be matched to a
2296 : : * separator key on the parent/target level.
2297 : : *
2298 : : * Don't apply OffsetNumberNext() to target_downlinkoffnum when we
2299 : : * already had to step right on the child level. Our traversal of
2300 : : * the child level must try to move in perfect lockstep behind (to
2301 : : * the left of) the target/parent level traversal.
2302 : : */
2303 [ + - ]: 1862 : if (blkno == downlink)
2304 : 1862 : pivotkey_offset = OffsetNumberNext(target_downlinkoffnum);
2305 : : else
2005 akorotkov@postgresql 2306 :UBC 0 : pivotkey_offset = target_downlinkoffnum;
2307 : :
1254 michael@paquier.xyz 2308 :CBC 1862 : topaque = BTPageGetOpaque(state->target);
2309 : :
2005 akorotkov@postgresql 2310 [ + - ]: 1862 : if (!offset_is_negative_infinity(topaque, pivotkey_offset))
2311 : : {
2312 : : /*
2313 : : * If we're looking for the next pivot tuple in target page,
2314 : : * but there is no more pivot tuples, then we should match to
2315 : : * high key instead.
2316 : : */
2317 [ + + ]: 1862 : if (pivotkey_offset > PageGetMaxOffsetNumber(state->target))
2318 : : {
2319 [ - + ]: 1 : if (P_RIGHTMOST(topaque))
2005 akorotkov@postgresql 2320 [ # # ]:UBC 0 : ereport(ERROR,
2321 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2322 : : errmsg("child high key is greater than rightmost pivot key on target level in index \"%s\"",
2323 : : RelationGetRelationName(state->rel)),
2324 : : errdetail_internal("Target block=%u child block=%u target page lsn=%X/%08X.",
2325 : : state->targetblock, blkno,
2326 : : LSN_FORMAT_ARGS(state->targetlsn))));
2005 akorotkov@postgresql 2327 :CBC 1 : pivotkey_offset = P_HIKEY;
2328 : : }
2329 : 1862 : itemid = PageGetItemIdCareful(state, state->targetblock,
2330 : : state->target, pivotkey_offset);
2331 : 1862 : itup = (IndexTuple) PageGetItem(state->target, itemid);
2332 : : }
2333 : : else
2334 : : {
2335 : : /*
2336 : : * We cannot try to match child's high key to a negative
2337 : : * infinity key in target, since there is nothing to compare.
2338 : : * However, it's still possible to match child's high key
2339 : : * outside of target page. The reason why we're are is that
2340 : : * bt_child_highkey_check() was previously called for the
2341 : : * cousin page of 'loaded_child', which is incomplete split.
2342 : : * So, now we traverse to the right of that cousin page and
2343 : : * current child level page under consideration still belongs
2344 : : * to the subtree of target's left sibling. Thus, we need to
2345 : : * match child's high key to its left uncle page high key.
2346 : : * Thankfully we saved it, it's called a "low key" of target
2347 : : * page.
2348 : : */
2005 akorotkov@postgresql 2349 [ # # ]:UBC 0 : if (!state->lowkey)
2350 [ # # ]: 0 : ereport(ERROR,
2351 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2352 : : errmsg("can't find left sibling high key in index \"%s\"",
2353 : : RelationGetRelationName(state->rel)),
2354 : : errdetail_internal("Target block=%u child block=%u target page lsn=%X/%08X.",
2355 : : state->targetblock, blkno,
2356 : : LSN_FORMAT_ARGS(state->targetlsn))));
2357 : 0 : itup = state->lowkey;
2358 : : }
2359 : :
1816 pg@bowt.ie 2360 [ - + ]:CBC 1862 : if (!bt_pivot_tuple_identical(state->heapkeyspace, highkey, itup))
2361 : : {
2005 akorotkov@postgresql 2362 [ # # ]:UBC 0 : ereport(ERROR,
2363 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2364 : : errmsg("mismatch between parent key and child high key in index \"%s\"",
2365 : : RelationGetRelationName(state->rel)),
2366 : : errdetail_internal("Target block=%u child block=%u target page lsn=%X/%08X.",
2367 : : state->targetblock, blkno,
2368 : : LSN_FORMAT_ARGS(state->targetlsn))));
2369 : : }
2370 : : }
2371 : :
2372 : : /* Exit if we already found next downlink */
2005 akorotkov@postgresql 2373 [ + - ]:CBC 1873 : if (blkno == downlink)
2374 : : {
2375 : 1873 : state->prevrightlink = opaque->btpo_next;
2376 : 1873 : state->previncompletesplit = rightsplit;
2377 : 1873 : return;
2378 : : }
2379 : :
2380 : : /* Traverse to the next page using rightlink */
2005 akorotkov@postgresql 2381 :UBC 0 : blkno = opaque->btpo_next;
2382 : :
2383 : : /* Free page contents if it's allocated by us */
2384 [ # # ]: 0 : if (page != loaded_child)
2385 : 0 : pfree(page);
2386 : 0 : first = false;
2387 : : }
2388 : : }
2389 : :
2390 : : /*
2391 : : * Checks one of target's downlink against its child page.
2392 : : *
2393 : : * Conceptually, the target page continues to be what is checked here. The
2394 : : * target block is still blamed in the event of finding an invariant violation.
2395 : : * The downlink insertion into the target is probably where any problem raised
2396 : : * here arises, and there is no such thing as a parent link, so doing the
2397 : : * verification this way around is much more practical.
2398 : : *
2399 : : * This function visits child page and it's sequentially called for each
2400 : : * downlink of target page. Assuming this we also check downlink connectivity
2401 : : * here in order to save child page visits.
2402 : : */
2403 : : static void
2005 akorotkov@postgresql 2404 :CBC 1861 : bt_child_check(BtreeCheckState *state, BTScanInsert targetkey,
2405 : : OffsetNumber downlinkoffnum)
2406 : : {
2407 : : ItemId itemid;
2408 : : IndexTuple itup;
2409 : : BlockNumber childblock;
2410 : : OffsetNumber offset;
2411 : : OffsetNumber maxoffset;
2412 : : Page child;
2413 : : BTPageOpaque copaque;
2414 : : BTPageOpaque topaque;
2415 : :
2416 : 1861 : itemid = PageGetItemIdCareful(state, state->targetblock,
2417 : : state->target, downlinkoffnum);
2418 : 1861 : itup = (IndexTuple) PageGetItem(state->target, itemid);
2419 : 1861 : childblock = BTreeTupleGetDownLink(itup);
2420 : :
2421 : : /*
2422 : : * Caller must have ShareLock on target relation, because of
2423 : : * considerations around page deletion by VACUUM.
2424 : : *
2425 : : * NB: In general, page deletion deletes the right sibling's downlink, not
2426 : : * the downlink of the page being deleted; the deleted page's downlink is
2427 : : * reused for its sibling. The key space is thereby consolidated between
2428 : : * the deleted page and its right sibling. (We cannot delete a parent
2429 : : * page's rightmost child unless it is the last child page, and we intend
2430 : : * to also delete the parent itself.)
2431 : : *
2432 : : * If this verification happened without a ShareLock, the following race
2433 : : * condition could cause false positives:
2434 : : *
2435 : : * In general, concurrent page deletion might occur, including deletion of
2436 : : * the left sibling of the child page that is examined here. If such a
2437 : : * page deletion were to occur, closely followed by an insertion into the
2438 : : * newly expanded key space of the child, a window for the false positive
2439 : : * opens up: the stale parent/target downlink originally followed to get
2440 : : * to the child legitimately ceases to be a lower bound on all items in
2441 : : * the page, since the key space was concurrently expanded "left".
2442 : : * (Insertion followed the "new" downlink for the child, not our now-stale
2443 : : * downlink, which was concurrently physically removed in target/parent as
2444 : : * part of deletion's first phase.)
2445 : : *
2446 : : * While we use various techniques elsewhere to perform cross-page
2447 : : * verification for !readonly callers, a similar trick seems difficult
2448 : : * here. The tricks used by bt_recheck_sibling_links and by
2449 : : * bt_right_page_check_scankey both involve verification of a same-level,
2450 : : * cross-sibling invariant. Cross-level invariants are far more squishy,
2451 : : * though. The nbtree REDO routines do not actually couple buffer locks
2452 : : * across levels during page splits, so making any cross-level check work
2453 : : * reliably in !readonly mode may be impossible.
2454 : : */
3103 andres@anarazel.de 2455 [ - + ]: 1861 : Assert(state->readonly);
2456 : :
2457 : : /*
2458 : : * Verify child page has the downlink key from target page (its parent) as
2459 : : * a lower bound; downlink must be strictly less than all keys on the
2460 : : * page.
2461 : : *
2462 : : * Check all items, rather than checking just the first and trusting that
2463 : : * the operator class obeys the transitive law.
2464 : : */
1254 michael@paquier.xyz 2465 : 1861 : topaque = BTPageGetOpaque(state->target);
3103 andres@anarazel.de 2466 : 1861 : child = palloc_btree_page(state, childblock);
1254 michael@paquier.xyz 2467 : 1861 : copaque = BTPageGetOpaque(child);
3103 andres@anarazel.de 2468 : 1861 : maxoffset = PageGetMaxOffsetNumber(child);
2469 : :
2470 : : /*
2471 : : * Since we've already loaded the child block, combine this check with
2472 : : * check for downlink connectivity.
2473 : : */
2005 akorotkov@postgresql 2474 : 1861 : bt_child_highkey_check(state, downlinkoffnum,
2475 : : child, topaque->btpo_level);
2476 : :
2477 : : /*
2478 : : * Since there cannot be a concurrent VACUUM operation in readonly mode,
2479 : : * and since a page has no links within other pages (siblings and parent)
2480 : : * once it is marked fully deleted, it should be impossible to land on a
2481 : : * fully deleted page.
2482 : : *
2483 : : * It does not quite make sense to enforce that the page cannot even be
2484 : : * half-dead, despite the fact the downlink is modified at the same stage
2485 : : * that the child leaf page is marked half-dead. That's incorrect because
2486 : : * there may occasionally be multiple downlinks from a chain of pages
2487 : : * undergoing deletion, where multiple successive calls are made to
2488 : : * _bt_unlink_halfdead_page() by VACUUM before it can finally safely mark
2489 : : * the leaf page as fully dead. While _bt_mark_page_halfdead() usually
2490 : : * removes the downlink to the leaf page that is marked half-dead, that's
2491 : : * not guaranteed, so it's possible we'll land on a half-dead page with a
2492 : : * downlink due to an interrupted multi-level page deletion.
2493 : : *
2494 : : * We go ahead with our checks if the child page is half-dead. It's safe
2495 : : * to do so because we do not test the child's high key, so it does not
2496 : : * matter that the original high key will have been replaced by a dummy
2497 : : * truncated high key within _bt_mark_page_halfdead(). All other page
2498 : : * items are left intact on a half-dead page, so there is still something
2499 : : * to test.
2500 : : */
2691 teodor@sigaev.ru 2501 [ - + ]: 1861 : if (P_ISDELETED(copaque))
2691 teodor@sigaev.ru 2502 [ # # ]:UBC 0 : ereport(ERROR,
2503 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2504 : : errmsg("downlink to deleted page found in index \"%s\"",
2505 : : RelationGetRelationName(state->rel)),
2506 : : errdetail_internal("Parent block=%u child block=%u parent page lsn=%X/%08X.",
2507 : : state->targetblock, childblock,
2508 : : LSN_FORMAT_ARGS(state->targetlsn))));
2509 : :
3103 andres@anarazel.de 2510 [ + + ]:CBC 1861 : for (offset = P_FIRSTDATAKEY(copaque);
2511 [ + + ]: 600350 : offset <= maxoffset;
2512 : 598489 : offset = OffsetNumberNext(offset))
2513 : : {
2514 : : /*
2515 : : * Skip comparison of target page key against "negative infinity"
2516 : : * item, if any. Checking it would indicate that it's not a strict
2517 : : * lower bound, but that's only because of the hard-coding for
2518 : : * negative infinity items within _bt_compare().
2519 : : *
2520 : : * If nbtree didn't truncate negative infinity tuples during internal
2521 : : * page splits then we'd expect child's negative infinity key to be
2522 : : * equal to the scankey/downlink from target/parent (it would be a
2523 : : * "low key" in this hypothetical scenario, and so it would still need
2524 : : * to be treated as a special case here).
2525 : : *
2526 : : * Negative infinity items can be thought of as a strict lower bound
2527 : : * that works transitively, with the last non-negative-infinity pivot
2528 : : * followed during a descent from the root as its "true" strict lower
2529 : : * bound. Only a small number of negative infinity items are truly
2530 : : * negative infinity; those that are the first items of leftmost
2531 : : * internal pages. In more general terms, a negative infinity item is
2532 : : * only negative infinity with respect to the subtree that the page is
2533 : : * at the root of.
2534 : : *
2535 : : * See also: bt_rootdescend(), which can even detect transitive
2536 : : * inconsistencies on cousin leaf pages.
2537 : : */
2538 [ + + ]: 598489 : if (offset_is_negative_infinity(copaque, offset))
2539 : 1 : continue;
2540 : :
2326 pg@bowt.ie 2541 [ - + ]: 598488 : if (!invariant_l_nontarget_offset(state, targetkey, childblock, child,
2542 : : offset))
3103 andres@anarazel.de 2543 [ # # ]:UBC 0 : ereport(ERROR,
2544 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2545 : : errmsg("down-link lower bound invariant violated for index \"%s\"",
2546 : : RelationGetRelationName(state->rel)),
2547 : : errdetail_internal("Parent block=%u child index tid=(%u,%u) parent page lsn=%X/%08X.",
2548 : : state->targetblock, childblock, offset,
2549 : : LSN_FORMAT_ARGS(state->targetlsn))));
2550 : : }
2551 : :
3103 andres@anarazel.de 2552 :CBC 1861 : pfree(child);
2553 : 1861 : }
2554 : :
2555 : : /*
2556 : : * Checks if page is missing a downlink that it should have.
2557 : : *
2558 : : * A page that lacks a downlink/parent may indicate corruption. However, we
2559 : : * must account for the fact that a missing downlink can occasionally be
2560 : : * encountered in a non-corrupt index. This can be due to an interrupted page
2561 : : * split, or an interrupted multi-level page deletion (i.e. there was a hard
2562 : : * crash or an error during a page split, or while VACUUM was deleting a
2563 : : * multi-level chain of pages).
2564 : : *
2565 : : * Note that this can only be called in readonly mode, so there is no need to
2566 : : * be concerned about concurrent page splits or page deletions.
2567 : : */
2568 : : static void
2005 akorotkov@postgresql 2569 :UBC 0 : bt_downlink_missing_check(BtreeCheckState *state, bool rightsplit,
2570 : : BlockNumber blkno, Page page)
2571 : : {
1254 michael@paquier.xyz 2572 : 0 : BTPageOpaque opaque = BTPageGetOpaque(page);
2573 : : ItemId itemid;
2574 : : IndexTuple itup;
2575 : : Page child;
2576 : : BTPageOpaque copaque;
2577 : : uint32 level;
2578 : : BlockNumber childblk;
2579 : : XLogRecPtr pagelsn;
2580 : :
2005 akorotkov@postgresql 2581 [ # # ]: 0 : Assert(state->readonly);
2582 [ # # ]: 0 : Assert(!P_IGNORE(opaque));
2583 : :
2584 : : /* No next level up with downlinks to fingerprint from the true root */
2585 [ # # ]: 0 : if (P_ISROOT(opaque))
2691 teodor@sigaev.ru 2586 : 0 : return;
2587 : :
2005 akorotkov@postgresql 2588 : 0 : pagelsn = PageGetLSN(page);
2589 : :
2590 : : /*
2591 : : * Incomplete (interrupted) page splits can account for the lack of a
2592 : : * downlink. Some inserting transaction should eventually complete the
2593 : : * page split in passing, when it notices that the left sibling page is
2594 : : * P_INCOMPLETE_SPLIT().
2595 : : *
2596 : : * In general, VACUUM is not prepared for there to be no downlink to a
2597 : : * page that it deletes. This is the main reason why the lack of a
2598 : : * downlink can be reported as corruption here. It's not obvious that an
2599 : : * invalid missing downlink can result in wrong answers to queries,
2600 : : * though, since index scans that land on the child may end up
2601 : : * consistently moving right. The handling of concurrent page splits (and
2602 : : * page deletions) within _bt_moveright() cannot distinguish
2603 : : * inconsistencies that last for a moment from inconsistencies that are
2604 : : * permanent and irrecoverable.
2605 : : *
2606 : : * VACUUM isn't even prepared to delete pages that have no downlink due to
2607 : : * an incomplete page split, but it can detect and reason about that case
2608 : : * by design, so it shouldn't be taken to indicate corruption. See
2609 : : * _bt_pagedel() for full details.
2610 : : */
2611 [ # # ]: 0 : if (rightsplit)
2612 : : {
2691 teodor@sigaev.ru 2613 [ # # ]: 0 : ereport(DEBUG1,
2614 : : (errcode(ERRCODE_NO_DATA),
2615 : : errmsg_internal("harmless interrupted page split detected in index \"%s\"",
2616 : : RelationGetRelationName(state->rel)),
2617 : : errdetail_internal("Block=%u level=%u left sibling=%u page lsn=%X/%08X.",
2618 : : blkno, opaque->btpo_level,
2619 : : opaque->btpo_prev,
2620 : : LSN_FORMAT_ARGS(pagelsn))));
2621 : 0 : return;
2622 : : }
2623 : :
2624 : : /*
2625 : : * Page under check is probably the "top parent" of a multi-level page
2626 : : * deletion. We'll need to descend the subtree to make sure that
2627 : : * descendant pages are consistent with that, though.
2628 : : *
2629 : : * If the page (which must be non-ignorable) is a leaf page, then clearly
2630 : : * it can't be the top parent. The lack of a downlink is probably a
2631 : : * symptom of a broad problem that could just as easily cause
2632 : : * inconsistencies anywhere else.
2633 : : */
2005 akorotkov@postgresql 2634 [ # # ]: 0 : if (P_ISLEAF(opaque))
2691 teodor@sigaev.ru 2635 [ # # ]: 0 : ereport(ERROR,
2636 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2637 : : errmsg("leaf index block lacks downlink in index \"%s\"",
2638 : : RelationGetRelationName(state->rel)),
2639 : : errdetail_internal("Block=%u page lsn=%X/%08X.",
2640 : : blkno,
2641 : : LSN_FORMAT_ARGS(pagelsn))));
2642 : :
2643 : : /* Descend from the given page, which is an internal page */
2644 [ # # ]: 0 : elog(DEBUG1, "checking for interrupted multi-level deletion due to missing downlink in index \"%s\"",
2645 : : RelationGetRelationName(state->rel));
2646 : :
1655 pg@bowt.ie 2647 : 0 : level = opaque->btpo_level;
2005 akorotkov@postgresql 2648 [ # # ]: 0 : itemid = PageGetItemIdCareful(state, blkno, page, P_FIRSTDATAKEY(opaque));
2649 : 0 : itup = (IndexTuple) PageGetItem(page, itemid);
2091 pg@bowt.ie 2650 : 0 : childblk = BTreeTupleGetDownLink(itup);
2651 : : for (;;)
2652 : : {
2691 teodor@sigaev.ru 2653 [ # # ]: 0 : CHECK_FOR_INTERRUPTS();
2654 : :
2655 : 0 : child = palloc_btree_page(state, childblk);
1254 michael@paquier.xyz 2656 : 0 : copaque = BTPageGetOpaque(child);
2657 : :
2691 teodor@sigaev.ru 2658 [ # # ]: 0 : if (P_ISLEAF(copaque))
2659 : 0 : break;
2660 : :
2661 : : /* Do an extra sanity check in passing on internal pages */
1655 pg@bowt.ie 2662 [ # # ]: 0 : if (copaque->btpo_level != level - 1)
2691 teodor@sigaev.ru 2663 [ # # ]: 0 : ereport(ERROR,
2664 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2665 : : errmsg_internal("downlink points to block in index \"%s\" whose level is not one level down",
2666 : : RelationGetRelationName(state->rel)),
2667 : : errdetail_internal("Top parent/under check block=%u block pointed to=%u expected level=%u level in pointed to block=%u.",
2668 : : blkno, childblk,
2669 : : level - 1, copaque->btpo_level)));
2670 : :
1655 pg@bowt.ie 2671 : 0 : level = copaque->btpo_level;
2326 2672 : 0 : itemid = PageGetItemIdCareful(state, childblk, child,
2673 [ # # ]: 0 : P_FIRSTDATAKEY(copaque));
2691 teodor@sigaev.ru 2674 : 0 : itup = (IndexTuple) PageGetItem(child, itemid);
2091 pg@bowt.ie 2675 : 0 : childblk = BTreeTupleGetDownLink(itup);
2676 : : /* Be slightly more pro-active in freeing this memory, just in case */
2691 teodor@sigaev.ru 2677 : 0 : pfree(child);
2678 : : }
2679 : :
2680 : : /*
2681 : : * Since there cannot be a concurrent VACUUM operation in readonly mode,
2682 : : * and since a page has no links within other pages (siblings and parent)
2683 : : * once it is marked fully deleted, it should be impossible to land on a
2684 : : * fully deleted page. See bt_child_check() for further details.
2685 : : *
2686 : : * The bt_child_check() P_ISDELETED() check is repeated here because
2687 : : * bt_child_check() does not visit pages reachable through negative
2688 : : * infinity items. Besides, bt_child_check() is unwilling to descend
2689 : : * multiple levels. (The similar bt_child_check() P_ISDELETED() check
2690 : : * within bt_check_level_from_leftmost() won't reach the page either,
2691 : : * since the leaf's live siblings should have their sibling links updated
2692 : : * to bypass the deletion target page when it is marked fully dead.)
2693 : : *
2694 : : * If this error is raised, it might be due to a previous multi-level page
2695 : : * deletion that failed to realize that it wasn't yet safe to mark the
2696 : : * leaf page as fully dead. A "dangling downlink" will still remain when
2697 : : * this happens. The fact that the dangling downlink's page (the leaf's
2698 : : * parent/ancestor page) lacked a downlink is incidental.
2699 : : */
2700 [ # # ]: 0 : if (P_ISDELETED(copaque))
2701 [ # # ]: 0 : ereport(ERROR,
2702 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2703 : : errmsg_internal("downlink to deleted leaf page found in index \"%s\"",
2704 : : RelationGetRelationName(state->rel)),
2705 : : errdetail_internal("Top parent/target block=%u leaf block=%u top parent/under check lsn=%X/%08X.",
2706 : : blkno, childblk,
2707 : : LSN_FORMAT_ARGS(pagelsn))));
2708 : :
2709 : : /*
2710 : : * Iff leaf page is half-dead, its high key top parent link should point
2711 : : * to what VACUUM considered to be the top parent page at the instant it
2712 : : * was interrupted. Provided the high key link actually points to the
2713 : : * page under check, the missing downlink we detected is consistent with
2714 : : * there having been an interrupted multi-level page deletion. This means
2715 : : * that the subtree with the page under check at its root (a page deletion
2716 : : * chain) is in a consistent state, enabling VACUUM to resume deleting the
2717 : : * entire chain the next time it encounters the half-dead leaf page.
2718 : : */
2719 [ # # # # ]: 0 : if (P_ISHALFDEAD(copaque) && !P_RIGHTMOST(copaque))
2720 : : {
2326 pg@bowt.ie 2721 : 0 : itemid = PageGetItemIdCareful(state, childblk, child, P_HIKEY);
2691 teodor@sigaev.ru 2722 : 0 : itup = (IndexTuple) PageGetItem(child, itemid);
2005 akorotkov@postgresql 2723 [ # # ]: 0 : if (BTreeTupleGetTopParent(itup) == blkno)
2691 teodor@sigaev.ru 2724 : 0 : return;
2725 : : }
2726 : :
2727 [ # # ]: 0 : ereport(ERROR,
2728 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2729 : : errmsg("internal index block lacks downlink in index \"%s\"",
2730 : : RelationGetRelationName(state->rel)),
2731 : : errdetail_internal("Block=%u level=%u page lsn=%X/%08X.",
2732 : : blkno, opaque->btpo_level,
2733 : : LSN_FORMAT_ARGS(pagelsn))));
2734 : : }
2735 : :
2736 : : /*
2737 : : * Per-tuple callback from table_index_build_scan, used to determine if index has
2738 : : * all the entries that definitely should have been observed in leaf pages of
2739 : : * the target index (that is, all IndexTuples that were fingerprinted by our
2740 : : * Bloom filter). All heapallindexed checks occur here.
2741 : : *
2742 : : * The redundancy between an index and the table it indexes provides a good
2743 : : * opportunity to detect corruption, especially corruption within the table.
2744 : : * The high level principle behind the verification performed here is that any
2745 : : * IndexTuple that should be in an index following a fresh CREATE INDEX (based
2746 : : * on the same index definition) should also have been in the original,
2747 : : * existing index, which should have used exactly the same representation
2748 : : *
2749 : : * Since the overall structure of the index has already been verified, the most
2750 : : * likely explanation for error here is a corrupt heap page (could be logical
2751 : : * or physical corruption). Index corruption may still be detected here,
2752 : : * though. Only readonly callers will have verified that left links and right
2753 : : * links are in agreement, and so it's possible that a leaf page transposition
2754 : : * within index is actually the source of corruption detected here (for
2755 : : * !readonly callers). The checks performed only for readonly callers might
2756 : : * more accurately frame the problem as a cross-page invariant issue (this
2757 : : * could even be due to recovery not replaying all WAL records). The !readonly
2758 : : * ERROR message raised here includes a HINT about retrying with readonly
2759 : : * verification, just in case it's a cross-page invariant issue, though that
2760 : : * isn't particularly likely.
2761 : : *
2762 : : * table_index_build_scan() expects to be able to find the root tuple when a
2763 : : * heap-only tuple (the live tuple at the end of some HOT chain) needs to be
2764 : : * indexed, in order to replace the actual tuple's TID with the root tuple's
2765 : : * TID (which is what we're actually passed back here). The index build heap
2766 : : * scan code will raise an error when a tuple that claims to be the root of the
2767 : : * heap-only tuple's HOT chain cannot be located. This catches cases where the
2768 : : * original root item offset/root tuple for a HOT chain indicates (for whatever
2769 : : * reason) that the entire HOT chain is dead, despite the fact that the latest
2770 : : * heap-only tuple should be indexed. When this happens, sequential scans may
2771 : : * always give correct answers, and all indexes may be considered structurally
2772 : : * consistent (i.e. the nbtree structural checks would not detect corruption).
2773 : : * It may be the case that only index scans give wrong answers, and yet heap or
2774 : : * SLRU corruption is the real culprit. (While it's true that LP_DEAD bit
2775 : : * setting will probably also leave the index in a corrupt state before too
2776 : : * long, the problem is nonetheless that there is heap corruption.)
2777 : : *
2778 : : * Heap-only tuple handling within table_index_build_scan() works in a way that
2779 : : * helps us to detect index tuples that contain the wrong values (values that
2780 : : * don't match the latest tuple in the HOT chain). This can happen when there
2781 : : * is no superseding index tuple due to a faulty assessment of HOT safety,
2782 : : * perhaps during the original CREATE INDEX. Because the latest tuple's
2783 : : * contents are used with the root TID, an error will be raised when a tuple
2784 : : * with the same TID but non-matching attribute values is passed back to us.
2785 : : * Faulty assessment of HOT-safety was behind at least two distinct CREATE
2786 : : * INDEX CONCURRENTLY bugs that made it into stable releases, one of which was
2787 : : * undetected for many years. In short, the same principle that allows a
2788 : : * REINDEX to repair corruption when there was an (undetected) broken HOT chain
2789 : : * also allows us to detect the corruption in many cases.
2790 : : */
2791 : : static void
2129 andres@anarazel.de 2792 :CBC 529914 : bt_tuple_present_callback(Relation index, ItemPointer tid, Datum *values,
2793 : : bool *isnull, bool tupleIsAlive, void *checkstate)
2794 : : {
2716 2795 : 529914 : BtreeCheckState *state = (BtreeCheckState *) checkstate;
2796 : : IndexTuple itup,
2797 : : norm;
2798 : :
2799 [ - + ]: 529914 : Assert(state->heapallindexed);
2800 : :
2801 : : /* Generate a normalized index tuple for fingerprinting */
2802 : 529914 : itup = index_form_tuple(RelationGetDescr(index), values, isnull);
2129 2803 : 529914 : itup->t_tid = *tid;
2404 pg@bowt.ie 2804 : 529914 : norm = bt_normalize_tuple(state, itup);
2805 : :
2806 : : /* Probe Bloom filter -- tuple should be present */
2807 [ - + ]: 529914 : if (bloom_lacks_element(state->filter, (unsigned char *) norm,
2808 : : IndexTupleSize(norm)))
2716 andres@anarazel.de 2809 [ # # # # ]:UBC 0 : ereport(ERROR,
2810 : : (errcode(ERRCODE_DATA_CORRUPTED),
2811 : : errmsg("heap tuple (%u,%u) from table \"%s\" lacks matching index tuple within index \"%s\"",
2812 : : ItemPointerGetBlockNumber(&(itup->t_tid)),
2813 : : ItemPointerGetOffsetNumber(&(itup->t_tid)),
2814 : : RelationGetRelationName(state->heaprel),
2815 : : RelationGetRelationName(state->rel)),
2816 : : !state->readonly
2817 : : ? errhint("Retrying verification using the function bt_index_parent_check() might provide a more specific error.")
2818 : : : 0));
2819 : :
2716 andres@anarazel.de 2820 :CBC 529914 : state->heaptuplespresent++;
2821 : 529914 : pfree(itup);
2822 : : /* Cannot leak memory here */
2404 pg@bowt.ie 2823 [ + + ]: 529914 : if (norm != itup)
2824 : 5 : pfree(norm);
2825 : 529914 : }
2826 : :
2827 : : /*
2828 : : * Normalize an index tuple for fingerprinting.
2829 : : *
2830 : : * In general, index tuple formation is assumed to be deterministic by
2831 : : * heapallindexed verification, and IndexTuples are assumed immutable. While
2832 : : * the LP_DEAD bit is mutable in leaf pages, that's ItemId metadata, which is
2833 : : * not fingerprinted. Normalization is required to compensate for corner
2834 : : * cases where the determinism assumption doesn't quite work.
2835 : : *
2836 : : * There is currently one such case: index_form_tuple() does not try to hide
2837 : : * the source TOAST state of input datums. The executor applies TOAST
2838 : : * compression for heap tuples based on different criteria to the compression
2839 : : * applied within btinsert()'s call to index_form_tuple(): it sometimes
2840 : : * compresses more aggressively, resulting in compressed heap tuple datums but
2841 : : * uncompressed corresponding index tuple datums. A subsequent heapallindexed
2842 : : * verification will get a logically equivalent though bitwise unequal tuple
2843 : : * from index_form_tuple(). False positive heapallindexed corruption reports
2844 : : * could occur without normalizing away the inconsistency.
2845 : : *
2846 : : * Returned tuple is often caller's own original tuple. Otherwise, it is a
2847 : : * new representation of caller's original index tuple, palloc()'d in caller's
2848 : : * memory context.
2849 : : *
2850 : : * Note: This routine is not concerned with distinctions about the
2851 : : * representation of tuples beyond those that might break heapallindexed
2852 : : * verification. In particular, it won't try to normalize opclass-equal
2853 : : * datums with potentially distinct representations (e.g., btree/numeric_ops
2854 : : * index datums will not get their display scale normalized-away here).
2855 : : * Caller does normalization for non-pivot tuples that have a posting list,
2856 : : * since dummy CREATE INDEX callback code generates new tuples with the same
2857 : : * normalized representation.
2858 : : */
2859 : : static IndexTuple
2860 : 1062216 : bt_normalize_tuple(BtreeCheckState *state, IndexTuple itup)
2861 : : {
2862 : 1062216 : TupleDesc tupleDescriptor = RelationGetDescr(state->rel);
2863 : : Datum normalized[INDEX_MAX_KEYS];
2864 : : bool isnull[INDEX_MAX_KEYS];
2865 : : bool need_free[INDEX_MAX_KEYS];
2866 : 1062216 : bool formnewtup = false;
2867 : : IndexTuple reformed;
2868 : : int i;
2869 : :
2870 : : /* Caller should only pass "logical" non-pivot tuples here */
2019 2871 [ + - - + ]: 1062216 : Assert(!BTreeTupleIsPosting(itup) && !BTreeTupleIsPivot(itup));
2872 : :
2873 : : /* Easy case: It's immediately clear that tuple has no varlena datums */
2404 2874 [ + + ]: 1062216 : if (!IndexTupleHasVarwidths(itup))
2875 : 1062192 : return itup;
2876 : :
2877 [ + + ]: 48 : for (i = 0; i < tupleDescriptor->natts; i++)
2878 : : {
2879 : : Form_pg_attribute att;
2880 : :
2881 : 24 : att = TupleDescAttr(tupleDescriptor, i);
2882 : :
2883 : : /* Assume untoasted/already normalized datum initially */
532 akorotkov@postgresql 2884 : 24 : need_free[i] = false;
2404 pg@bowt.ie 2885 : 24 : normalized[i] = index_getattr(itup, att->attnum,
2886 : : tupleDescriptor,
2887 : : &isnull[i]);
2888 [ + - + - : 24 : if (att->attbyval || att->attlen != -1 || isnull[i])
- + ]
2404 pg@bowt.ie 2889 :UBC 0 : continue;
2890 : :
2891 : : /*
2892 : : * Callers always pass a tuple that could safely be inserted into the
2893 : : * index without further processing, so an external varlena header
2894 : : * should never be encountered here
2895 : : */
2404 pg@bowt.ie 2896 [ - + ]:CBC 24 : if (VARATT_IS_EXTERNAL(DatumGetPointer(normalized[i])))
2404 pg@bowt.ie 2897 [ # # ]:UBC 0 : ereport(ERROR,
2898 : : (errcode(ERRCODE_INDEX_CORRUPTED),
2899 : : errmsg("external varlena datum in tuple that references heap row (%u,%u) in index \"%s\"",
2900 : : ItemPointerGetBlockNumber(&(itup->t_tid)),
2901 : : ItemPointerGetOffsetNumber(&(itup->t_tid)),
2902 : : RelationGetRelationName(state->rel))));
532 akorotkov@postgresql 2903 [ + + + + ]:CBC 46 : else if (!VARATT_IS_COMPRESSED(DatumGetPointer(normalized[i])) &&
2904 [ + + ]: 22 : VARSIZE(DatumGetPointer(normalized[i])) > TOAST_INDEX_TARGET &&
2905 [ + + ]: 21 : (att->attstorage == TYPSTORAGE_EXTENDED ||
2906 [ - + ]: 16 : att->attstorage == TYPSTORAGE_MAIN))
2907 : : {
2908 : : /*
2909 : : * This value will be compressed by index_form_tuple() with the
2910 : : * current storage settings. We may be here because this tuple
2911 : : * was formed with different storage settings. So, force forming.
2912 : : */
2913 : 5 : formnewtup = true;
2914 : : }
2404 pg@bowt.ie 2915 [ + + ]: 19 : else if (VARATT_IS_COMPRESSED(DatumGetPointer(normalized[i])))
2916 : : {
2917 : 2 : formnewtup = true;
2918 : 2 : normalized[i] = PointerGetDatum(PG_DETOAST_DATUM(normalized[i]));
532 akorotkov@postgresql 2919 : 2 : need_free[i] = true;
2920 : : }
2921 : :
2922 : : /*
2923 : : * Short tuples may have 1B or 4B header. Convert 4B header of short
2924 : : * tuples to 1B
2925 : : */
2926 [ + + + + ]: 17 : else if (VARATT_CAN_MAKE_SHORT(DatumGetPointer(normalized[i])))
2927 : : {
2928 : : /* convert to short varlena */
2929 : 1 : Size len = VARATT_CONVERTED_SHORT_SIZE(DatumGetPointer(normalized[i]));
2930 : 1 : char *data = palloc(len);
2931 : :
2932 : 1 : SET_VARSIZE_SHORT(data, len);
2933 : 1 : memcpy(data + 1, VARDATA(DatumGetPointer(normalized[i])), len - 1);
2934 : :
2935 : 1 : formnewtup = true;
2936 : 1 : normalized[i] = PointerGetDatum(data);
2937 : 1 : need_free[i] = true;
2938 : : }
2939 : : }
2940 : :
2941 : : /*
2942 : : * Easier case: Tuple has varlena datums, none of which are compressed or
2943 : : * short with 4B header
2944 : : */
2404 pg@bowt.ie 2945 [ + + ]: 24 : if (!formnewtup)
2946 : 16 : return itup;
2947 : :
2948 : : /*
2949 : : * Hard case: Tuple had compressed varlena datums that necessitate
2950 : : * creating normalized version of the tuple from uncompressed input datums
2951 : : * (normalized input datums). This is rather naive, but shouldn't be
2952 : : * necessary too often.
2953 : : *
2954 : : * In the heap, tuples may contain short varlena datums with both 1B
2955 : : * header and 4B headers. But the corresponding index tuple should always
2956 : : * have such varlena's with 1B headers. So, if there is a short varlena
2957 : : * with 4B header, we need to convert it for fingerprinting.
2958 : : *
2959 : : * Note that we rely on deterministic index_form_tuple() TOAST compression
2960 : : * of normalized input.
2961 : : */
2962 : 8 : reformed = index_form_tuple(tupleDescriptor, normalized, isnull);
2963 : 8 : reformed->t_tid = itup->t_tid;
2964 : :
2965 : : /* Cannot leak memory here */
2966 [ + + ]: 16 : for (i = 0; i < tupleDescriptor->natts; i++)
532 akorotkov@postgresql 2967 [ + + ]: 8 : if (need_free[i])
2404 pg@bowt.ie 2968 : 3 : pfree(DatumGetPointer(normalized[i]));
2969 : :
2970 : 8 : return reformed;
2971 : : }
2972 : :
2973 : : /*
2974 : : * Produce palloc()'d "plain" tuple for nth posting list entry/TID.
2975 : : *
2976 : : * In general, deduplication is not supposed to change the logical contents of
2977 : : * an index. Multiple index tuples are merged together into one equivalent
2978 : : * posting list index tuple when convenient.
2979 : : *
2980 : : * heapallindexed verification must normalize-away this variation in
2981 : : * representation by converting posting list tuples into two or more "plain"
2982 : : * tuples. Each tuple must be fingerprinted separately -- there must be one
2983 : : * tuple for each corresponding Bloom filter probe during the heap scan.
2984 : : *
2985 : : * Note: Caller still needs to call bt_normalize_tuple() with returned tuple.
2986 : : */
2987 : : static inline IndexTuple
2019 2988 : 25523 : bt_posting_plain_tuple(IndexTuple itup, int n)
2989 : : {
2990 [ - + ]: 25523 : Assert(BTreeTupleIsPosting(itup));
2991 : :
2992 : : /* Returns non-posting-list tuple */
2993 : 25523 : return _bt_form_posting(itup, BTreeTupleGetPostingN(itup, n), 1);
2994 : : }
2995 : :
2996 : : /*
2997 : : * Search for itup in index, starting from fast root page. itup must be a
2998 : : * non-pivot tuple. This is only supported with heapkeyspace indexes, since
2999 : : * we rely on having fully unique keys to find a match with only a single
3000 : : * visit to a leaf page, barring an interrupted page split, where we may have
3001 : : * to move right. (A concurrent page split is impossible because caller must
3002 : : * be readonly caller.)
3003 : : *
3004 : : * This routine can detect very subtle transitive consistency issues across
3005 : : * more than one level of the tree. Leaf pages all have a high key (even the
3006 : : * rightmost page has a conceptual positive infinity high key), but not a low
3007 : : * key. Their downlink in parent is a lower bound, which along with the high
3008 : : * key is almost enough to detect every possible inconsistency. A downlink
3009 : : * separator key value won't always be available from parent, though, because
3010 : : * the first items of internal pages are negative infinity items, truncated
3011 : : * down to zero attributes during internal page splits. While it's true that
3012 : : * bt_child_check() and the high key check can detect most imaginable key
3013 : : * space problems, there are remaining problems it won't detect with non-pivot
3014 : : * tuples in cousin leaf pages. Starting a search from the root for every
3015 : : * existing leaf tuple detects small inconsistencies in upper levels of the
3016 : : * tree that cannot be detected any other way. (Besides all this, this is
3017 : : * probably also useful as a direct test of the code used by index scans
3018 : : * themselves.)
3019 : : */
3020 : : static bool
2362 3021 : 201098 : bt_rootdescend(BtreeCheckState *state, IndexTuple itup)
3022 : : {
3023 : : BTScanInsert key;
3024 : : BTStack stack;
3025 : : Buffer lbuf;
3026 : : bool exists;
3027 : :
819 3028 : 201098 : key = _bt_mkscankey(state->rel, itup);
2362 3029 [ + - - + ]: 201098 : Assert(key->heapkeyspace && key->scantid != NULL);
3030 : :
3031 : : /*
3032 : : * Search from root.
3033 : : *
3034 : : * Ideally, we would arrange to only move right within _bt_search() when
3035 : : * an interrupted page split is detected (i.e. when the incomplete split
3036 : : * bit is found to be set), but for now we accept the possibility that
3037 : : * that could conceal an inconsistency.
3038 : : */
3039 [ + - - + ]: 201098 : Assert(state->readonly && state->rootdescend);
3040 : 201098 : exists = false;
729 tmunro@postgresql.or 3041 : 201098 : stack = _bt_search(state->rel, NULL, key, &lbuf, BT_READ);
3042 : :
2362 pg@bowt.ie 3043 [ + - ]: 201098 : if (BufferIsValid(lbuf))
3044 : : {
3045 : : BTInsertStateData insertstate;
3046 : : OffsetNumber offnum;
3047 : : Page page;
3048 : :
3049 : 201098 : insertstate.itup = itup;
3050 : 201098 : insertstate.itemsz = MAXALIGN(IndexTupleSize(itup));
3051 : 201098 : insertstate.itup_key = key;
2019 3052 : 201098 : insertstate.postingoff = 0;
2362 3053 : 201098 : insertstate.bounds_valid = false;
3054 : 201098 : insertstate.buf = lbuf;
3055 : :
3056 : : /* Get matching tuple on leaf page */
3057 : 201098 : offnum = _bt_binsrch_insert(state->rel, &insertstate);
3058 : : /* Compare first >= matching item on leaf page, if any */
3059 : 201098 : page = BufferGetPage(lbuf);
3060 : : /* Should match on first heap TID when tuple has a posting list */
3061 [ + - ]: 201098 : if (offnum <= PageGetMaxOffsetNumber(page) &&
2019 3062 [ + - + - ]: 402196 : insertstate.postingoff <= 0 &&
2362 3063 : 201098 : _bt_compare(state->rel, key, page, offnum) == 0)
3064 : 201098 : exists = true;
3065 : 201098 : _bt_relbuf(state->rel, lbuf);
3066 : : }
3067 : :
3068 : 201098 : _bt_freestack(stack);
3069 : 201098 : pfree(key);
3070 : :
3071 : 201098 : return exists;
3072 : : }
3073 : :
3074 : : /*
3075 : : * Is particular offset within page (whose special state is passed by caller)
3076 : : * the page negative-infinity item?
3077 : : *
3078 : : * As noted in comments above _bt_compare(), there is special handling of the
3079 : : * first data item as a "negative infinity" item. The hard-coding within
3080 : : * _bt_compare() makes comparing this item for the purposes of verification
3081 : : * pointless at best, since the IndexTuple only contains a valid TID (a
3082 : : * reference TID to child page).
3083 : : */
3084 : : static inline bool
3103 andres@anarazel.de 3085 : 2653382 : offset_is_negative_infinity(BTPageOpaque opaque, OffsetNumber offset)
3086 : : {
3087 : : /*
3088 : : * For internal pages only, the first item after high key, if any, is
3089 : : * negative infinity item. Internal pages always have a negative infinity
3090 : : * item, whereas leaf pages never have one. This implies that negative
3091 : : * infinity item is either first or second line item, or there is none
3092 : : * within page.
3093 : : *
3094 : : * Negative infinity items are a special case among pivot tuples. They
3095 : : * always have zero attributes, while all other pivot tuples always have
3096 : : * nkeyatts attributes.
3097 : : *
3098 : : * Right-most pages don't have a high key, but could be said to
3099 : : * conceptually have a "positive infinity" high key. Thus, there is a
3100 : : * symmetry between down link items in parent pages, and high keys in
3101 : : * children. Together, they represent the part of the key space that
3102 : : * belongs to each page in the index. For example, all children of the
3103 : : * root page will have negative infinity as a lower bound from root
3104 : : * negative infinity downlink, and positive infinity as an upper bound
3105 : : * (implicitly, from "imaginary" positive infinity high key in root).
3106 : : */
3107 [ + + + + : 2653382 : return !P_ISLEAF(opaque) && offset == P_FIRSTDATAKEY(opaque);
+ + ]
3108 : : }
3109 : :
3110 : : /*
3111 : : * Does the invariant hold that the key is strictly less than a given upper
3112 : : * bound offset item?
3113 : : *
3114 : : * Verifies line pointer on behalf of caller.
3115 : : *
3116 : : * If this function returns false, convention is that caller throws error due
3117 : : * to corruption.
3118 : : */
3119 : : static inline bool
2362 pg@bowt.ie 3120 : 2043759 : invariant_l_offset(BtreeCheckState *state, BTScanInsert key,
3121 : : OffsetNumber upperbound)
3122 : : {
3123 : : ItemId itemid;
3124 : : int32 cmp;
3125 : :
638 3126 [ + - - + ]: 2043759 : Assert(!key->nextkey && key->backward);
3127 : :
3128 : : /* Verify line pointer before checking tuple */
2326 3129 : 2043759 : itemid = PageGetItemIdCareful(state, state->targetblock, state->target,
3130 : : upperbound);
3131 : : /* pg_upgrade'd indexes may legally have equal sibling tuples */
2362 3132 [ - + ]: 2043759 : if (!key->heapkeyspace)
2362 pg@bowt.ie 3133 :UBC 0 : return invariant_leq_offset(state, key, upperbound);
3134 : :
2362 pg@bowt.ie 3135 :CBC 2043759 : cmp = _bt_compare(state->rel, key, state->target, upperbound);
3136 : :
3137 : : /*
3138 : : * _bt_compare() is capable of determining that a scankey with a
3139 : : * filled-out attribute is greater than pivot tuples where the comparison
3140 : : * is resolved at a truncated attribute (value of attribute in pivot is
3141 : : * minus infinity). However, it is not capable of determining that a
3142 : : * scankey is _less than_ a tuple on the basis of a comparison resolved at
3143 : : * _scankey_ minus infinity attribute. Complete an extra step to simulate
3144 : : * having minus infinity values for omitted scankey attribute(s).
3145 : : */
3146 [ - + ]: 2043759 : if (cmp == 0)
3147 : : {
3148 : : BTPageOpaque topaque;
3149 : : IndexTuple ritup;
3150 : : int uppnkeyatts;
3151 : : ItemPointer rheaptid;
3152 : : bool nonpivot;
3153 : :
2362 pg@bowt.ie 3154 :UBC 0 : ritup = (IndexTuple) PageGetItem(state->target, itemid);
1254 michael@paquier.xyz 3155 : 0 : topaque = BTPageGetOpaque(state->target);
2362 pg@bowt.ie 3156 [ # # # # : 0 : nonpivot = P_ISLEAF(topaque) && upperbound >= P_FIRSTDATAKEY(topaque);
# # ]
3157 : :
3158 : : /* Get number of keys + heap TID for item to the right */
3159 [ # # # # : 0 : uppnkeyatts = BTreeTupleGetNKeyAtts(ritup, state->rel);
# # ]
3160 : 0 : rheaptid = BTreeTupleGetHeapTIDCareful(state, ritup, nonpivot);
3161 : :
3162 : : /* Heap TID is tiebreaker key attribute */
3163 [ # # ]: 0 : if (key->keysz == uppnkeyatts)
3164 [ # # # # ]: 0 : return key->scantid == NULL && rheaptid != NULL;
3165 : :
3166 : 0 : return key->keysz < uppnkeyatts;
3167 : : }
3168 : :
2362 pg@bowt.ie 3169 :CBC 2043759 : return cmp < 0;
3170 : : }
3171 : :
3172 : : /*
3173 : : * Does the invariant hold that the key is less than or equal to a given upper
3174 : : * bound offset item?
3175 : : *
3176 : : * Caller should have verified that upperbound's line pointer is consistent
3177 : : * using PageGetItemIdCareful() call.
3178 : : *
3179 : : * If this function returns false, convention is that caller throws error due
3180 : : * to corruption.
3181 : : */
3182 : : static inline bool
3183 : 1881637 : invariant_leq_offset(BtreeCheckState *state, BTScanInsert key,
3184 : : OffsetNumber upperbound)
3185 : : {
3186 : : int32 cmp;
3187 : :
638 3188 [ + - - + ]: 1881637 : Assert(!key->nextkey && key->backward);
3189 : :
2362 3190 : 1881637 : cmp = _bt_compare(state->rel, key, state->target, upperbound);
3191 : :
3103 andres@anarazel.de 3192 : 1881637 : return cmp <= 0;
3193 : : }
3194 : :
3195 : : /*
3196 : : * Does the invariant hold that the key is strictly greater than a given lower
3197 : : * bound offset item?
3198 : : *
3199 : : * Caller should have verified that lowerbound's line pointer is consistent
3200 : : * using PageGetItemIdCareful() call.
3201 : : *
3202 : : * If this function returns false, convention is that caller throws error due
3203 : : * to corruption.
3204 : : */
3205 : : static inline bool
2362 pg@bowt.ie 3206 : 6803 : invariant_g_offset(BtreeCheckState *state, BTScanInsert key,
3207 : : OffsetNumber lowerbound)
3208 : : {
3209 : : int32 cmp;
3210 : :
638 3211 [ + - - + ]: 6803 : Assert(!key->nextkey && key->backward);
3212 : :
2362 3213 : 6803 : cmp = _bt_compare(state->rel, key, state->target, lowerbound);
3214 : :
3215 : : /* pg_upgrade'd indexes may legally have equal sibling tuples */
3216 [ - + ]: 6803 : if (!key->heapkeyspace)
2362 pg@bowt.ie 3217 :UBC 0 : return cmp >= 0;
3218 : :
3219 : : /*
3220 : : * No need to consider the possibility that scankey has attributes that we
3221 : : * need to force to be interpreted as negative infinity. _bt_compare() is
3222 : : * able to determine that scankey is greater than negative infinity. The
3223 : : * distinction between "==" and "<" isn't interesting here, since
3224 : : * corruption is indicated either way.
3225 : : */
2362 pg@bowt.ie 3226 :CBC 6803 : return cmp > 0;
3227 : : }
3228 : :
3229 : : /*
3230 : : * Does the invariant hold that the key is strictly less than a given upper
3231 : : * bound offset item, with the offset relating to a caller-supplied page that
3232 : : * is not the current target page?
3233 : : *
3234 : : * Caller's non-target page is a child page of the target, checked as part of
3235 : : * checking a property of the target page (i.e. the key comes from the
3236 : : * target). Verifies line pointer on behalf of caller.
3237 : : *
3238 : : * If this function returns false, convention is that caller throws error due
3239 : : * to corruption.
3240 : : */
3241 : : static inline bool
3242 : 598488 : invariant_l_nontarget_offset(BtreeCheckState *state, BTScanInsert key,
3243 : : BlockNumber nontargetblock, Page nontarget,
3244 : : OffsetNumber upperbound)
3245 : : {
3246 : : ItemId itemid;
3247 : : int32 cmp;
3248 : :
638 3249 [ + - - + ]: 598488 : Assert(!key->nextkey && key->backward);
3250 : :
3251 : : /* Verify line pointer before checking tuple */
2326 3252 : 598488 : itemid = PageGetItemIdCareful(state, nontargetblock, nontarget,
3253 : : upperbound);
2362 3254 : 598488 : cmp = _bt_compare(state->rel, key, nontarget, upperbound);
3255 : :
3256 : : /* pg_upgrade'd indexes may legally have equal sibling tuples */
3257 [ - + ]: 598488 : if (!key->heapkeyspace)
2362 pg@bowt.ie 3258 :UBC 0 : return cmp <= 0;
3259 : :
3260 : : /* See invariant_l_offset() for an explanation of this extra step */
2362 pg@bowt.ie 3261 [ + + ]:CBC 598488 : if (cmp == 0)
3262 : : {
3263 : : IndexTuple child;
3264 : : int uppnkeyatts;
3265 : : ItemPointer childheaptid;
3266 : : BTPageOpaque copaque;
3267 : : bool nonpivot;
3268 : :
3269 : 1860 : child = (IndexTuple) PageGetItem(nontarget, itemid);
1254 michael@paquier.xyz 3270 : 1860 : copaque = BTPageGetOpaque(nontarget);
2362 pg@bowt.ie 3271 [ + - + + : 1860 : nonpivot = P_ISLEAF(copaque) && upperbound >= P_FIRSTDATAKEY(copaque);
+ - ]
3272 : :
3273 : : /* Get number of keys + heap TID for child/non-target item */
3274 [ - + + + : 1860 : uppnkeyatts = BTreeTupleGetNKeyAtts(child, state->rel);
- + ]
3275 : 1860 : childheaptid = BTreeTupleGetHeapTIDCareful(state, child, nonpivot);
3276 : :
3277 : : /* Heap TID is tiebreaker key attribute */
3278 [ + - ]: 1860 : if (key->keysz == uppnkeyatts)
3279 [ + - + - ]: 1860 : return key->scantid == NULL && childheaptid != NULL;
3280 : :
2362 pg@bowt.ie 3281 :UBC 0 : return key->keysz < uppnkeyatts;
3282 : : }
3283 : :
2362 pg@bowt.ie 3284 :CBC 596628 : return cmp < 0;
3285 : : }
3286 : :
3287 : : /*
3288 : : * Given a block number of a B-Tree page, return page in palloc()'d memory.
3289 : : * While at it, perform some basic checks of the page.
3290 : : *
3291 : : * There is never an attempt to get a consistent view of multiple pages using
3292 : : * multiple concurrent buffer locks; in general, we only acquire a single pin
3293 : : * and buffer lock at a time, which is often all that the nbtree code requires.
3294 : : * (Actually, bt_recheck_sibling_links couples buffer locks, which is the only
3295 : : * exception to this general rule.)
3296 : : *
3297 : : * Operating on a copy of the page is useful because it prevents control
3298 : : * getting stuck in an uninterruptible state when an underlying operator class
3299 : : * misbehaves.
3300 : : */
3301 : : static Page
3103 andres@anarazel.de 3302 : 21942 : palloc_btree_page(BtreeCheckState *state, BlockNumber blocknum)
3303 : : {
3304 : : Buffer buffer;
3305 : : Page page;
3306 : : BTPageOpaque opaque;
3307 : : OffsetNumber maxoffset;
3308 : :
3309 : 21942 : page = palloc(BLCKSZ);
3310 : :
3311 : : /*
3312 : : * We copy the page into local storage to avoid holding pin on the buffer
3313 : : * longer than we must.
3314 : : */
3315 : 21942 : buffer = ReadBufferExtended(state->rel, MAIN_FORKNUM, blocknum, RBM_NORMAL,
3316 : : state->checkstrategy);
3317 : 21930 : LockBuffer(buffer, BT_READ);
3318 : :
3319 : : /*
3320 : : * Perform the same basic sanity checking that nbtree itself performs for
3321 : : * every page:
3322 : : */
3323 : 21930 : _bt_checkpage(state->rel, buffer);
3324 : :
3325 : : /* Only use copy of page in palloc()'d memory */
3326 : 21930 : memcpy(page, BufferGetPage(buffer), BLCKSZ);
3327 : 21930 : UnlockReleaseBuffer(buffer);
3328 : :
1254 michael@paquier.xyz 3329 : 21930 : opaque = BTPageGetOpaque(page);
3330 : :
2910 tgl@sss.pgh.pa.us 3331 [ + + - + ]: 21930 : if (P_ISMETA(opaque) && blocknum != BTREE_METAPAGE)
3103 andres@anarazel.de 3332 [ # # ]:UBC 0 : ereport(ERROR,
3333 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3334 : : errmsg("invalid meta page found at block %u in index \"%s\"",
3335 : : blocknum, RelationGetRelationName(state->rel))));
3336 : :
3337 : : /* Check page from block that ought to be meta page */
3103 andres@anarazel.de 3338 [ + + ]:CBC 21930 : if (blocknum == BTREE_METAPAGE)
3339 : : {
3340 : 3963 : BTMetaPageData *metad = BTPageGetMeta(page);
3341 : :
2910 tgl@sss.pgh.pa.us 3342 [ + - ]: 3963 : if (!P_ISMETA(opaque) ||
3103 andres@anarazel.de 3343 [ - + ]: 3963 : metad->btm_magic != BTREE_MAGIC)
3103 andres@anarazel.de 3344 [ # # ]:UBC 0 : ereport(ERROR,
3345 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3346 : : errmsg("index \"%s\" meta page is corrupt",
3347 : : RelationGetRelationName(state->rel))));
3348 : :
2712 teodor@sigaev.ru 3349 [ + - ]:CBC 3963 : if (metad->btm_version < BTREE_MIN_VERSION ||
3350 [ - + ]: 3963 : metad->btm_version > BTREE_VERSION)
3103 andres@anarazel.de 3351 [ # # ]:UBC 0 : ereport(ERROR,
3352 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3353 : : errmsg("version mismatch in index \"%s\": file version %d, "
3354 : : "current version %d, minimum supported version %d",
3355 : : RelationGetRelationName(state->rel),
3356 : : metad->btm_version, BTREE_VERSION,
3357 : : BTREE_MIN_VERSION)));
3358 : :
3359 : : /* Finished with metapage checks */
2691 teodor@sigaev.ru 3360 :CBC 3963 : return page;
3361 : : }
3362 : :
3363 : : /*
3364 : : * Deleted pages that still use the old 32-bit XID representation have no
3365 : : * sane "level" field because they type pun the field, but all other pages
3366 : : * (including pages deleted on Postgres 14+) have a valid value.
3367 : : */
1655 pg@bowt.ie 3368 [ - + - - ]: 17967 : if (!P_ISDELETED(opaque) || P_HAS_FULLXID(opaque))
3369 : : {
3370 : : /* Okay, no reason not to trust btpo_level field from page */
3371 : :
3372 [ + + - + ]: 17967 : if (P_ISLEAF(opaque) && opaque->btpo_level != 0)
1655 pg@bowt.ie 3373 [ # # ]:UBC 0 : ereport(ERROR,
3374 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3375 : : errmsg_internal("invalid leaf page level %u for block %u in index \"%s\"",
3376 : : opaque->btpo_level, blocknum,
3377 : : RelationGetRelationName(state->rel))));
3378 : :
1655 pg@bowt.ie 3379 [ + + - + ]:CBC 17967 : if (!P_ISLEAF(opaque) && opaque->btpo_level == 0)
1655 pg@bowt.ie 3380 [ # # ]:UBC 0 : ereport(ERROR,
3381 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3382 : : errmsg_internal("invalid internal page level 0 for block %u in index \"%s\"",
3383 : : blocknum,
3384 : : RelationGetRelationName(state->rel))));
3385 : : }
3386 : :
3387 : : /*
3388 : : * Sanity checks for number of items on page.
3389 : : *
3390 : : * As noted at the beginning of _bt_binsrch(), an internal page must have
3391 : : * children, since there must always be a negative infinity downlink
3392 : : * (there may also be a highkey). In the case of non-rightmost leaf
3393 : : * pages, there must be at least a highkey. The exceptions are deleted
3394 : : * pages, which contain no items.
3395 : : *
3396 : : * This is correct when pages are half-dead, since internal pages are
3397 : : * never half-dead, and leaf pages must have a high key when half-dead
3398 : : * (the rightmost page can never be deleted). It's also correct with
3399 : : * fully deleted pages: _bt_unlink_halfdead_page() doesn't change anything
3400 : : * about the target page other than setting the page as fully dead, and
3401 : : * setting its xact field. In particular, it doesn't change the sibling
3402 : : * links in the deletion target itself, since they're required when index
3403 : : * scans land on the deletion target, and then need to move right (or need
3404 : : * to move left, in the case of backward index scans).
3405 : : */
2691 teodor@sigaev.ru 3406 :CBC 17967 : maxoffset = PageGetMaxOffsetNumber(page);
3407 [ - + ]: 17967 : if (maxoffset > MaxIndexTuplesPerPage)
2691 teodor@sigaev.ru 3408 [ # # ]:UBC 0 : ereport(ERROR,
3409 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3410 : : errmsg("Number of items on block %u of index \"%s\" exceeds MaxIndexTuplesPerPage (%u)",
3411 : : blocknum, RelationGetRelationName(state->rel),
3412 : : MaxIndexTuplesPerPage)));
3413 : :
1941 akorotkov@postgresql 3414 [ + + + - :CBC 17967 : if (!P_ISLEAF(opaque) && !P_ISDELETED(opaque) && maxoffset < P_FIRSTDATAKEY(opaque))
+ + - + ]
2691 teodor@sigaev.ru 3415 [ # # ]:UBC 0 : ereport(ERROR,
3416 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3417 : : errmsg("internal block %u in index \"%s\" lacks high key and/or at least one downlink",
3418 : : blocknum, RelationGetRelationName(state->rel))));
3419 : :
1941 akorotkov@postgresql 3420 [ + + + - :CBC 17967 : if (P_ISLEAF(opaque) && !P_ISDELETED(opaque) && !P_RIGHTMOST(opaque) && maxoffset < P_HIKEY)
+ + - + ]
2691 teodor@sigaev.ru 3421 [ # # ]:UBC 0 : ereport(ERROR,
3422 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3423 : : errmsg("non-rightmost leaf block %u in index \"%s\" lacks high key item",
3424 : : blocknum, RelationGetRelationName(state->rel))));
3425 : :
3426 : : /*
3427 : : * In general, internal pages are never marked half-dead, except on
3428 : : * versions of Postgres prior to 9.4, where it can be valid transient
3429 : : * state. This state is nonetheless treated as corruption by VACUUM on
3430 : : * from version 9.4 on, so do the same here. See _bt_pagedel() for full
3431 : : * details.
3432 : : */
2691 teodor@sigaev.ru 3433 [ + + - + ]:CBC 17967 : if (!P_ISLEAF(opaque) && P_ISHALFDEAD(opaque))
2691 teodor@sigaev.ru 3434 [ # # ]:UBC 0 : ereport(ERROR,
3435 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3436 : : errmsg("internal page block %u in index \"%s\" is half-dead",
3437 : : blocknum, RelationGetRelationName(state->rel)),
3438 : : errhint("This can be caused by an interrupted VACUUM in version 9.3 or older, before upgrade. Please REINDEX it.")));
3439 : :
3440 : : /*
3441 : : * Check that internal pages have no garbage items, and that no page has
3442 : : * an invalid combination of deletion-related page level flags
3443 : : */
3103 andres@anarazel.de 3444 [ + + - + ]:CBC 17967 : if (!P_ISLEAF(opaque) && P_HAS_GARBAGE(opaque))
3103 andres@anarazel.de 3445 [ # # ]:UBC 0 : ereport(ERROR,
3446 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3447 : : errmsg_internal("internal page block %u in index \"%s\" has garbage items",
3448 : : blocknum, RelationGetRelationName(state->rel))));
3449 : :
1655 pg@bowt.ie 3450 [ - + - - ]:CBC 17967 : if (P_HAS_FULLXID(opaque) && !P_ISDELETED(opaque))
1655 pg@bowt.ie 3451 [ # # ]:UBC 0 : ereport(ERROR,
3452 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3453 : : errmsg_internal("full transaction id page flag appears in non-deleted block %u in index \"%s\"",
3454 : : blocknum, RelationGetRelationName(state->rel))));
3455 : :
1655 pg@bowt.ie 3456 [ - + - - ]:CBC 17967 : if (P_ISDELETED(opaque) && P_ISHALFDEAD(opaque))
1655 pg@bowt.ie 3457 [ # # ]:UBC 0 : ereport(ERROR,
3458 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3459 : : errmsg_internal("deleted page block %u in index \"%s\" is half-dead",
3460 : : blocknum, RelationGetRelationName(state->rel))));
3461 : :
3103 andres@anarazel.de 3462 :CBC 17967 : return page;
3463 : : }
3464 : :
3465 : : /*
3466 : : * _bt_mkscankey() wrapper that automatically prevents insertion scankey from
3467 : : * being considered greater than the pivot tuple that its values originated
3468 : : * from (or some other identical pivot tuple) in the common case where there
3469 : : * are truncated/minus infinity attributes. Without this extra step, there
3470 : : * are forms of corruption that amcheck could theoretically fail to report.
3471 : : *
3472 : : * For example, invariant_g_offset() might miss a cross-page invariant failure
3473 : : * on an internal level if the scankey built from the first item on the
3474 : : * target's right sibling page happened to be equal to (not greater than) the
3475 : : * last item on target page. The !backward tiebreaker in _bt_compare() might
3476 : : * otherwise cause amcheck to assume (rather than actually verify) that the
3477 : : * scankey is greater.
3478 : : */
3479 : : static inline BTScanInsert
819 pg@bowt.ie 3480 : 2059277 : bt_mkscankey_pivotsearch(Relation rel, IndexTuple itup)
3481 : : {
3482 : : BTScanInsert skey;
3483 : :
3484 : 2059277 : skey = _bt_mkscankey(rel, itup);
638 3485 : 2059277 : skey->backward = true;
3486 : :
2362 3487 : 2059277 : return skey;
3488 : : }
3489 : :
3490 : : /*
3491 : : * PageGetItemId() wrapper that validates returned line pointer.
3492 : : *
3493 : : * Buffer page/page item access macros generally trust that line pointers are
3494 : : * not corrupt, which might cause problems for verification itself. For
3495 : : * example, there is no bounds checking in PageGetItem(). Passing it a
3496 : : * corrupt line pointer can cause it to return a tuple/pointer that is unsafe
3497 : : * to dereference.
3498 : : *
3499 : : * Validating line pointers before tuples avoids undefined behavior and
3500 : : * assertion failures with corrupt indexes, making the verification process
3501 : : * more robust and predictable.
3502 : : */
3503 : : static ItemId
2326 3504 : 4718766 : PageGetItemIdCareful(BtreeCheckState *state, BlockNumber block, Page page,
3505 : : OffsetNumber offset)
3506 : : {
3507 : 4718766 : ItemId itemid = PageGetItemId(page, offset);
3508 : :
3509 [ - + ]: 4718766 : if (ItemIdGetOffset(itemid) + ItemIdGetLength(itemid) >
3510 : : BLCKSZ - MAXALIGN(sizeof(BTPageOpaqueData)))
2326 pg@bowt.ie 3511 [ # # ]:UBC 0 : ereport(ERROR,
3512 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3513 : : errmsg("line pointer points past end of tuple space in index \"%s\"",
3514 : : RelationGetRelationName(state->rel)),
3515 : : errdetail_internal("Index tid=(%u,%u) lp_off=%u, lp_len=%u lp_flags=%u.",
3516 : : block, offset, ItemIdGetOffset(itemid),
3517 : : ItemIdGetLength(itemid),
3518 : : ItemIdGetFlags(itemid))));
3519 : :
3520 : : /*
3521 : : * Verify that line pointer isn't LP_REDIRECT or LP_UNUSED, since nbtree
3522 : : * never uses either. Verify that line pointer has storage, too, since
3523 : : * even LP_DEAD items should within nbtree.
3524 : : */
2326 pg@bowt.ie 3525 [ + - + - ]:CBC 4718766 : if (ItemIdIsRedirected(itemid) || !ItemIdIsUsed(itemid) ||
3526 [ - + ]: 4718766 : ItemIdGetLength(itemid) == 0)
2326 pg@bowt.ie 3527 [ # # ]:UBC 0 : ereport(ERROR,
3528 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3529 : : errmsg("invalid line pointer storage in index \"%s\"",
3530 : : RelationGetRelationName(state->rel)),
3531 : : errdetail_internal("Index tid=(%u,%u) lp_off=%u, lp_len=%u lp_flags=%u.",
3532 : : block, offset, ItemIdGetOffset(itemid),
3533 : : ItemIdGetLength(itemid),
3534 : : ItemIdGetFlags(itemid))));
3535 : :
2326 pg@bowt.ie 3536 :CBC 4718766 : return itemid;
3537 : : }
3538 : :
3539 : : /*
3540 : : * BTreeTupleGetHeapTID() wrapper that enforces that a heap TID is present in
3541 : : * cases where that is mandatory (i.e. for non-pivot tuples)
3542 : : */
3543 : : static inline ItemPointer
2362 3544 : 1860 : BTreeTupleGetHeapTIDCareful(BtreeCheckState *state, IndexTuple itup,
3545 : : bool nonpivot)
3546 : : {
3547 : : ItemPointer htid;
3548 : :
3549 : : /*
3550 : : * Caller determines whether this is supposed to be a pivot or non-pivot
3551 : : * tuple using page type and item offset number. Verify that tuple
3552 : : * metadata agrees with this.
3553 : : */
2019 3554 [ - + ]: 1860 : Assert(state->heapkeyspace);
3555 [ - + - - ]: 1860 : if (BTreeTupleIsPivot(itup) && nonpivot)
2019 pg@bowt.ie 3556 [ # # ]:UBC 0 : ereport(ERROR,
3557 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3558 : : errmsg_internal("block %u or its right sibling block or child block in index \"%s\" has unexpected pivot tuple",
3559 : : state->targetblock,
3560 : : RelationGetRelationName(state->rel))));
3561 : :
2019 pg@bowt.ie 3562 [ + - - + ]:CBC 1860 : if (!BTreeTupleIsPivot(itup) && !nonpivot)
2019 pg@bowt.ie 3563 [ # # ]:UBC 0 : ereport(ERROR,
3564 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3565 : : errmsg_internal("block %u or its right sibling block or child block in index \"%s\" has unexpected non-pivot tuple",
3566 : : state->targetblock,
3567 : : RelationGetRelationName(state->rel))));
3568 : :
2019 pg@bowt.ie 3569 :CBC 1860 : htid = BTreeTupleGetHeapTID(itup);
3570 [ - + - - ]: 1860 : if (!ItemPointerIsValid(htid) && nonpivot)
2362 pg@bowt.ie 3571 [ # # ]:UBC 0 : ereport(ERROR,
3572 : : (errcode(ERRCODE_INDEX_CORRUPTED),
3573 : : errmsg("block %u or its right sibling block or child block in index \"%s\" contains non-pivot tuple that lacks a heap TID",
3574 : : state->targetblock,
3575 : : RelationGetRelationName(state->rel))));
3576 : :
2019 pg@bowt.ie 3577 :CBC 1860 : return htid;
3578 : : }
3579 : :
3580 : : /*
3581 : : * Return the "pointed to" TID for itup, which is used to generate a
3582 : : * descriptive error message. itup must be a "data item" tuple (it wouldn't
3583 : : * make much sense to call here with a high key tuple, since there won't be a
3584 : : * valid downlink/block number to display).
3585 : : *
3586 : : * Returns either a heap TID (which will be the first heap TID in posting list
3587 : : * if itup is posting list tuple), or a TID that contains downlink block
3588 : : * number, plus some encoded metadata (e.g., the number of attributes present
3589 : : * in itup).
3590 : : */
3591 : : static inline ItemPointer
3592 : 6 : BTreeTupleGetPointsToTID(IndexTuple itup)
3593 : : {
3594 : : /*
3595 : : * Rely on the assumption that !heapkeyspace internal page data items will
3596 : : * correctly return TID with downlink here -- BTreeTupleGetHeapTID() won't
3597 : : * recognize it as a pivot tuple, but everything still works out because
3598 : : * the t_tid field is still returned
3599 : : */
3600 [ + + ]: 6 : if (!BTreeTupleIsPivot(itup))
3601 : 4 : return BTreeTupleGetHeapTID(itup);
3602 : :
3603 : : /* Pivot tuple returns TID with downlink block (heapkeyspace variant) */
3604 : 2 : return &itup->t_tid;
3605 : : }
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